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LS factory computer pinouts: P01, P59 and E38 for a standalone harness
Factory GM computer pinouts for LS swaps: every wired pin on the P01/P59 (1999–2007) and E38 (Gen IV) connectors, with wire color, GM circuit number, what it does and what to keep or delete when you trim the factory harness into a standalone.
Read this first
- Disconnect the battery before you de-pin or splice anything.
- Go by pin number and circuit, not color. GM reused colors, and harnesses differ by year, options and plant. Check against the wiring diagram for your exact vehicle.
- Never probe computer pins with a test light; it can damage the driver. Use a digital multimeter and back-probe.
- The computer still needs a tune: VATS off, and any sensor you delete (rear O2, EVAP, EGR, air pump) turned off in the calibration.
Key: Keep Wire to car Auto trans Optional
Keep = the engine needs it. Wire to car = runs to something in the vehicle (power, tach, fuel pump relay, data port). Auto trans = only with a computer-controlled 4L60E/4L80E. Optional = emissions, 4WD, gauges and features you can drop if your build and your state allow it.
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P01 / P59 "0411" style, 1999–2002 (blue C1 + red C2)
The 1999–2002 truck, van and F-body computers with a blue and a red 80-pin connector. Common service numbers: 09354896 (1999–2000) and 12200411 (2001–2002, the "0411"). This list is for the 4.8, 5.3 and 6.0 truck harness. F-body and Corvette harnesses are close but put some references and grounds on different pins.
P01 / P59 "0411" style: connector C1 (blue)
| Pin | Wire | Circuit | Function | Standalone harness |
|---|---|---|---|---|
| 1 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 2 | LT GRN | 1867 | Crankshaft Position Sensor B+ Supply | Keep Engine sensor or output. Keep. |
| 3 | PNK/BLK | 1746 | Injector 3 Control | Keep Engine sensor or output. Keep. |
| 4 | LT GRN/BLK | 1745 | Injector 2 Control | Keep Engine sensor or output. Keep. |
| 11 | LT BLU | 1876 | Knock Sensor Signal Rear | Keep Engine sensor or output. Keep. |
| 12 | DK BLU/WHT | 1869 | Crankshaft Position Sensor Signal | Keep Engine sensor or output. Keep. |
| 13 | ORN/BLK | 463 | Requested Torque Signal (NW7) | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 14 | ORN/BLK | 1061 | UART Serial Data (drive by wire only) | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 15 | DK BLU/WHT | 774 | UART Serial Data (drive by wire only) | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 17 | DK BLU | 1225 | Transmission Fluid Pressure Switch B | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 18 | RED | 1226 | Transmission Fluid Pressure Switch C | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 19 | PNK | 439 | PCM Ignition Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 20 | ORN | 440 | PCM Battery Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 21 | YEL/BLK | 1868 | Crankshaft Position Sensor Ground | Keep Engine sensor or output. Keep. |
| 23 | PPL | 719 | Sensor Ground EGR | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 25 | TAN | 1671 | HO2S Signal Low B2S2 (w/Case Ground O2 Sensors) | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 25 | TAN | 413 | HO2S Signal Low B2S2 (w/Isolated Ground O2 Sensors) | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 26 | TAN | 1667 | HO2S Signal Low B2S1 (w/Case Ground O2 Sensors) | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 26 | TAN | 413 | HO2S Signal Low B2S1 (w/Isolated Ground O2 Sensors) | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 28 | TAN/WHT | 1669 | HO2S Signal Low B1S2 (w/Case Ground O2 Sensors) | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 28 | TAN | 413 | HO2S Signal Low B1S2 (w/Isolated Ground O2 Sensors) | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 29 | TAN/WHT | 1653 | HO2S Signal Low B1S1 (w/Case Ground O2 Sensors) | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 29 | TAN | 413 | HO2S Signal Low B1S1 (w/Isolated Ground O2 Sensors) | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 30 | LT GRN | 1478 | Engine Coolant Level Switch | Optional Optional input. Keep only if you use that feature or gauge. |
| 32 | BLK/WHT | 771 | PRND A Input | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 33 | PPL | 420 | TCC Brake Switch | Wire to car Brake switch. 12 V with the pedal pressed. Needed for converter lockup, cruise and drive-by-wire. |
| 34 | WHT | 776 | PRND P Input | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. This pin can be programmed to read a single park/neutral switch wire when no range switch is fitted. |
| 35 | GRA | 48 | Clutch Switch Signal (manual trans) | Wire to car Clutch switch (manual transmission). |
| 36 | BLK | 1744 | Injector 1 Control | Keep Engine sensor or output. Keep. |
| 37 | YEL/BLK | 846 | Injector 6 Control | Keep Engine sensor or output. Keep. |
| 38 | PNK/WHT | 1101 | Damping Lift/Drive Signal | Optional Optional input. Keep only if you use that feature or gauge. |
| 40 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 41 | BLK | 407 | Sensor Ground (Trans) w/Case grounded o2 Sensors | Keep O2 sensor ground or heater circuit. Keep it if any O2 sensor on that circuit stays. |
| 41 | GRY | 720 | Sensor Ground (Trans, ETC) w/Isolated Ground O2 Sensors | Keep O2 sensor ground or heater circuit. Keep it if any O2 sensor on that circuit stays. |
| 42 | – | – | Empty cavity | Wire to car Empty from the factory. Add a terminal here for fan 1 relay control. |
| 43 | RED/BLK | 877 | Injector 7 Control | Keep Engine sensor or output. Keep. |
| 44 | LT BLU/BLK | 844 | Injector 4 Control | Keep Engine sensor or output. Keep. |
| 45 | GRA | 474 | Fuel Tank Pressure Sensor 5V Reference | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 46 | GRA | 416 | TP Sensor 5V Reference | Keep Engine sensor or output. Keep. |
| 47 | GRA | 597 | MAP Sensor 5V Reference | Keep Engine sensor or output. Keep. |
| 48 | GRA | 596 | EGR Pintle Position Sensor 5V Reference | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 51 | DK BLU | 496 | Knock Sensor Signal Front | Keep Engine sensor or output. Keep. |
| 53 | BLK | 470 | Fuel Tank Pressure Sensor Ground | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 54 | BLK | 452 | TP Sensor Ground | Keep Engine sensor or output. Keep. |
| 55 | BRN | 1456 | EGR Pintle Position Sensor Signal | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 56 | WHT | – | Fuel Temp/Composition Signal (L59 Flex Fuel) | Optional Flex-fuel sensor input. Needs a flex-fuel operating system and the sensor. |
| 57 | ORN | 440 | PCM Battery Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 58 | DK GRN | 1049 | Serial Data to OBD2 Port | Wire to car Data line. Run the OBD-II one to the diagnostic port so you can scan and flash. Others go to factory modules you may not keep. |
| 59 | YEL | 710 | Serial Data to BCM | Wire to car Data line. Run the OBD-II one to the diagnostic port so you can scan and flash. Others go to factory modules you may not keep. |
| 60 | ORN/BLK | 469 | MAP Sensor Ground | Keep Engine sensor or output. Keep. |
| 61 | PNK/BLK | 632 | CMP Sensor Ground | Keep Engine sensor or output. Keep. |
| 63 | GRY | 720 | Sensor Ground (ETC) w/case grounded o2 sensors | Keep O2 sensor ground or heater circuit. Keep it if any O2 sensor on that circuit stays. |
| 63 | TAN | 413 | Sensor Ground (HO2S Low Signal) w/isolated grounded o2 sensors | Keep O2 sensor ground or heater circuit. Keep it if any O2 sensor on that circuit stays. |
| 65 | PPL | 1670 | HO2S Signal High Bank 2 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 66 | PPL | 1666 | HO2S Signal High Bank 2 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 68 | PPL/WHT | 1668 | HO2S Signal High Bank 1 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 69 | PPL/WHT | 1665 | HO2S Signal High Bank 1 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 70 | BRN | 1174 | Low Oil Level Switch | Optional Optional input. Keep only if you use that feature or gauge. |
| 71 | – | – | Empty cavity | Wire to car Empty from the factory. Add a terminal here for tow/haul mode switch input. |
| 72 | YEL | 772 | PRND B Input | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 73 | BRN/WHT | 633 | Camshaft Position (CMP) Sensor Signal | Keep Engine sensor or output. Keep. |
| 74 | YEL | 410 | Engine Coolant Temperature (ECT) Sensor Signal | Keep Engine sensor or output. Keep. |
| 75 | PNK | 1020 | PCM Ignition Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 76 | BLK/WHT | 845 | Injector 5 Control | Keep Engine sensor or output. Keep. |
| 77 | DK BLU/WHT | 878 | Injector 8 Control | Keep Engine sensor or output. Keep. |
| 79 | WHT | 687 | 3-2 Shift Solenoid Control | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 80 | ORN/BLK | 510 | Fuel Level Sensor Ground | Keep Engine sensor or output. Keep. |
P01 / P59 "0411" style: connector C2 (red)
| Pin | Wire | Circuit | Function | Standalone harness |
|---|---|---|---|---|
| 1 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 2 | BRN | 418 | TCC Control Solenoid | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 3 | TAN | 1465 | Fuel Pump Relay Control - Secondary | Wire to car Fuel pump relay control. Keep: wire it to the pump relay coil (secondary is for dual-tank trucks). |
| 5 | TAN/BLK | 464 | Delivered Torque Signal | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 6 | RED/BLK | 1228 | Transmission Fluid Pressure Control Solenoid High | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 7 | RED | 1676 | EGR Solenoid Supply | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 8 | LT BLU/WHT | 1229 | Transmission Fluid Pressure Control Solenoid Low | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 9 | DK GRN/WHT | 465 | Fuel Pump Relay Control | Wire to car Fuel pump relay control. Keep: wire it to the pump relay coil (secondary is for dual-tank trucks). |
| 10 | WHT | 121 | Engine Speed (Tach) Output Signal | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. |
| 11 | DK BLU | 604 | A/C High Pressure Recirculation Switch | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 13 | LT BLU/BLK | 396 | Cruise Control Engage Signal | Optional Optional input. Keep only if you use that feature or gauge. |
| 15 | BRN | 25 | Generator L Terminal (Alternator turn on signal) | Wire to car Alternator turn-on (L terminal). Needed with the factory alternator; some later trucks route this through a battery-current module instead. |
| 16 | GRA/BLK | 1694 | 4 Wheel Drive Switch Signal Low | Optional Optional 4WD input. Keep only with the factory transfer case and axle switches. |
| 17 | DK GRN/WHT | 762 | A/C Request Signal | Wire to car A/C. Keep only if the computer will control the A/C compressor. Check: Circuit number differs by source (762 or 2523); wire color and pin agree. |
| 19 | BLK/WHT | 1695 | 4 Wheel Drive Front Axle Switch | Optional Optional 4WD input. Keep only with the factory transfer case and axle switches. |
| 20 | LT GRN/BLK | 822 | Vehicle Speed Sensor (VSS) Reference Low | Keep Speed sensor input. Keep: the computer needs vehicle speed. |
| 21 | PPL/WHT | 821 | Vehicle Speed Sensor (VSS) Signal | Keep Speed sensor input. Keep: the computer needs vehicle speed. |
| 22 | RED/BLK | 1230 | Vehicle Speed Sensor (VSS) Signal (4L80E Only) | Auto trans 4L80E input shaft speed (or a 4WD transfer-case speed input on some trucks). Keep with a 4L80E. |
| 23 | DK BLU/WHT | 1231 | Vehicle Speed Sensor (VSS) Reference Low (4L80E Only) | Auto trans 4L80E input shaft speed (or a 4WD transfer-case speed input on some trucks). Keep with a 4L80E. |
| 24 | DK BLU | 417 | TP Sensor Signal | Keep Engine sensor or output. Keep. |
| 25 | TAN | 472 | IAT Sensor Signal | Keep Engine sensor or output. Keep. |
| 26 | PPL | 2121 | Ignition Control 1 | Keep Engine sensor or output. Keep. |
| 27 | RED | 2127 | Ignition Control 7 | Keep Engine sensor or output. Keep. |
| 28 | LT BLU/WHT | 2126 | Ignition Control 6 | Keep Engine sensor or output. Keep. |
| 29 | DK GRN/WHT | 2124 | Ignition Control 4 | Keep Engine sensor or output. Keep. |
| 31 | YEL | 492 | MAF Sensor Signal | Keep Engine sensor or output. Keep. |
| 32 | LT GRN | 432 | MAP Sensor Signal | Keep Engine sensor or output. Keep. |
| 33 | DK GRN | 1614 | HVAC Recirculation Door Control | Wire to car Factory HVAC door control. In a swap this cavity is commonly re-used for the second cooling-fan relay. |
| 34 | DK GRN/WHT | 428 | EVAP Canister Purge Solenoid Control | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 36 | BRN | 436 | AIR Pump Relay Control (w/NC1) | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 38 | – | – | Empty cavity | Wire to car Empty from the factory. Add a terminal here for pwm fuel gauge signal output. |
| 39 | RED | 631 | CMP Sensor B+ Supply | Keep Engine sensor or output. Keep. |
| 40 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 41 | WHT | 257 | EGR Solenoid Ground | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 42 | TAN/BLK | 422 | TCC Enable Circuit (4L60-E only) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 43 | DK GRN/WHT | 459 | A/C Clutch Relay Control | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 45 | WHT | 1310 | EVAP Canister Vent Valve Control | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 46 | BRN/WHT | 419 | Malfunction Indicator Lamp (MIL) Control | Wire to car Check-engine light. Run to a dash light. |
| 47 | YEL/BLK | 1223 | Transmission Shift Solenoid B | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 48 | LT GRN | 1222 | Transmission Shift Solenoid A | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 49 | YEL/BLK | 1827 | Vehicle Speed Output Circuit 128K | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. |
| 50 | DK GRN/WHT | 817 | Vehicle Speed Output Circuit 4K | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. |
| 51 | YEL/BLK | 1227 | Transmission Temperature Sensor Signal | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 52 | GRY | 23 | Generator Field Duty Cycle Signal | Wire to car Alternator control. Keep with a factory computer-controlled alternator. |
| 54 | PPL | 1589 | Fuel Level Sensor Signal | Optional Optional input. Keep only if you use that feature or gauge. |
| 55 | DK GRN | 603 | A/C Low Pressure Switch Signal | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 57 | BLK | 552 | IAT Sensor Ground | Keep Engine sensor or output. Keep. |
| 60 | BRN | 2129 | Ignition Control Reference Low Bank 1 | Keep Engine sensor or output. Keep. |
| 61 | BRN/WHT | 2130 | Ignition Control Reference Low Bank 2 | Keep Engine sensor or output. Keep. |
| 62 | GRA | 773 | PRND C | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 63 | PNK | 1224 | Transmission Fluid Pressure Switch A | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 64 | DK GRN | 890 | Fuel Tank Pressure Sensor Signal | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 66 | PPL/WHT | 2128 | Ignition Control 8 | Keep Engine sensor or output. Keep. |
| 67 | RED/WHT | 2122 | Ignition Control 2 | Keep Engine sensor or output. Keep. |
| 68 | DK GRN | 2125 | Ignition Control 5 | Keep Engine sensor or output. Keep. |
| 69 | LT BLU | 2123 | Ignition Control 3 | Keep Engine sensor or output. Keep. |
| 73 | DK BLU | 1936 | Fuel Level Sensor Signal - Secondary | Optional Optional input. Keep only if you use that feature or gauge. |
| 74 | LT GRN/WHT | 3213 | HO2S Heater Control (w/isolated grounded sensors) (2001-02 6.0L Only) | Keep O2 sensor ground or heater circuit. Keep it if any O2 sensor on that circuit stays. |
| 76 | LT GRN/WHT | 1749 | IAC Coil B High | Keep Engine sensor or output. Keep. |
| 77 | LT GRN/BLK | 444 | IAC Coil B Low | Keep Engine sensor or output. Keep. |
| 78 | LT BLU/BLK | 1748 | IAC Coil A Low | Keep Engine sensor or output. Keep. |
| 79 | LT BLU/WHT | 1747 | IAC Coil A High | Keep Engine sensor or output. Keep. |
| 80 | LT GRN | 3212 | HO2S Heater Low Reference (w/isolated ground sensors, 2001-02 6.0L only) | Keep O2 sensor ground or heater circuit. Keep it if any O2 sensor on that circuit stays. |
P59, 2003–2007 trucks (blue C1 + green C2)
2003–2007 GM truck and SUV computers (P59) with a blue and a green 80-pin connector, from a 2004 4.8/5.3/6.0 harness. Cable-throttle and drive-by-wire trucks differ on a few pins, noted in the table.
P59: connector C1 (blue)
| Pin | Wire | Circuit | Function | Standalone harness |
|---|---|---|---|---|
| 1 | BLK/WHT | 451 | Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 2 | LT GRN | 1867 | 12 Volt Reference | Keep Engine sensor or output. Keep. |
| 3 | PNK/BLK | 1746 | Fuel Injector 3 Control | Keep Engine sensor or output. Keep. |
| 4 | LT GRN/BLK | 1745 | Fuel Injector 2 Control | Keep Engine sensor or output. Keep. |
| 7 | GRY | 2705 | 5 Volt Reference (OIL PRESSURE) | Keep Engine sensor or output. Keep. |
| 8 | GRY | – | 5 Volt Reference (Throttle Position Sensor Pin A) Cable Throttle ONLY | Keep Cable-throttle P59s only (throttle position sensor). Not used with drive-by-wire. |
| 11 | LT BLU | 1876 | Knock Sensor 2 Signal | Keep Engine sensor or output. Keep. |
| 12 | DK BLU/WHT | 1869 | CKP Sensor Signal | Keep Engine sensor or output. Keep. |
| 13 | ORN/BLK | 463 | Requested Torque Signal (NW7) | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 14 | ORN/BLK | 1061 | UART Serial Data (drive by wire only) | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 15 | DK BLU/WHT | 774 | UART Serial Data (drive by wire only) | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 17 | DK BLU | 1225 | Transmission Fluid Pressure Switch Signal B (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 18 | RED | 1226 | Transmission Fluid Pressure Switch Signal C (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 19 | PNK | 439 | PCM Ignition Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 20 | ORN | 440 | PCM Battery Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 21 | YEL/BLK | 1868 | Crankshaft Position Sensor Ground | Keep Engine sensor or output. Keep. |
| 23 | BLK | 470 | Low Reference | Keep Engine sensor or output. Keep. |
| 24 | BLK/WHT | 451 | Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 25 | TAN | 1671 | HO2S Low Signal - Bank 2 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 26 | TAN | 1667 | HO2S Low Signal - Bank 2 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 27 | BLK/WHT | 451 | Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 28 | TAN/WHT | 1669 | HO2S Low Signal - Bank 1 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 29 | TAN | 1664 | HO2S Low Signal - Bank 1 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 30 | LT GRN | 1478 | Coolant Level Switch Signal (empty 2006+) | Optional Optional input. Keep only if you use that feature or gauge. |
| 32 | BLK/WHT | 771 | Transmission Range Switch Signal A (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 33 | PPL | 420 | TCC Brake Switch/Cruise Control Release Switch Signal | Wire to car Brake switch. 12 V with the pedal pressed. Needed for converter lockup, cruise and drive-by-wire. |
| 34 | WHT | 776 | Transmission Range Switch Signal P (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. This pin can be programmed to read a single park/neutral switch wire when no range switch is fitted. |
| 35 | GRY | 48 | CPP Switch Signal (M/T) | Wire to car Clutch switch (manual transmission). |
| 36 | BLK | 1744 | Fuel Injector 1 Control | Keep Engine sensor or output. Keep. |
| 37 | YEL/BLK | 846 | Fuel Injector 6 Control | Keep Engine sensor or output. Keep. |
| 38 | PNK/WHT | 1101 | Damping Lift/Dive Signal | Optional Optional input. Keep only if you use that feature or gauge. |
| 39 | YEL/BLK | 625 | Starter Enable Relay Control | Wire to car Starter relay control (on some vehicles only). |
| 40 | BLK/WHT | 451 | Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 42 | – | – | Empty cavity | Wire to car Empty from the factory. Add a terminal here for fan 1 relay control. Some 2005 and later harnesses already have it. |
| 43 | RED/BLK | 877 | Fuel Injector 7 Control | Keep Engine sensor or output. Keep. |
| 44 | LT BLU/BLK | 844 | Fuel Injector 4 Control | Keep Engine sensor or output. Keep. |
| 45 | GRY | 2700 | 5 Volt Reference (A/C) | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 46 | GRY | 474 | 5 Volt Reference (EVA) | Keep Engine sensor or output. Keep. |
| 48 | GRY | 597 | 5 Volt Reference (MAP) | Keep Engine sensor or output. Keep. |
| 51 | DK BLU | 496 | Knock Sensor 1 Signal | Keep Engine sensor or output. Keep. |
| 53 | GRY | 720 | Low Reference (TRANS) | Keep Engine sensor or output. Keep. |
| 54 | ORN/BLK | 469 | Low Reference (MAP) | Keep Engine sensor or output. Keep. |
| 56 | WHT | 1579 | Fuel Temperature/Composition Signal (L59) Flex Fuel Sensor | Optional Flex-fuel sensor input. Needs a flex-fuel operating system and the sensor. |
| 57 | ORN | 440 | PCM Battery Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 58 | DK GRN | 1049 | Class 2 Serial Data | Wire to car Data line. Run the OBD-II one to the diagnostic port so you can scan and flash. Others go to factory modules you may not keep. |
| 59 | YEL | 710 | Class 2 Serial Data | Wire to car Data line. Run the OBD-II one to the diagnostic port so you can scan and flash. Others go to factory modules you may not keep. |
| 60 | BLK | – | Low Reference (Throttle Position Sensor Pin B) Cable Throttle ONLY | Keep Cable-throttle P59s only (throttle position sensor). Not used with drive-by-wire. |
| 61 | PNK/BLK | 632 | Low Reference (CMP) | Keep Engine sensor or output. Keep. |
| 63 | BLK | 2755 | Low Reference (OIL PRESSURE SENSOR) | Keep Engine sensor or output. Keep. |
| 64 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 65 | PPL | 1670 | HO2S High Signal - Bank 2 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 66 | PPL | 1666 | HO2S High Signal - Bank 2 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 67 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 68 | PPL/WHT | 1668 | HO2S High Signal - Bank 1 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 69 | PPL/WHT | 1665 | HO2S High Signal - Bank 1 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 70 | BRN | 1174 | Oil Level Switch Signal | Optional Optional input. Keep only if you use that feature or gauge. |
| 72 | YEL | 772 | Transmission Range Switch Signal B (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 73 | BRN/WHT | 633 | CMP Sensor Signal | Keep Engine sensor or output. Keep. |
| 74 | YEL | 410 | ECT Sensor Signal | Keep Engine sensor or output. Keep. |
| 75 | PNK | 1020 | PCM Ignition Supply | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 76 | BLK/WHT | 845 | Fuel Injector 5 Control | Keep Engine sensor or output. Keep. |
| 77 | DK BLU/WHT | 878 | Fuel Injector 8 Control | Keep Engine sensor or output. Keep. |
| 79 | WHT | 687 | 3-2 Shift Solenoid Valve Control (M30/M32) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 80 | BLK | 407 | Low Reference (ECT) | Keep Engine sensor or output. Keep. |
P59: connector C2 (green)
| Pin | Wire | Circuit | Function | Standalone harness |
|---|---|---|---|---|
| 1 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 2 | BRN | 418 | TCC PWM Solenoid Valve Control (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 3 | TAN | 1465 | Fuel Pump Relay Control - Secondary (Dual Tanks) | Wire to car Fuel pump relay control. Keep: wire it to the pump relay coil (secondary is for dual-tank trucks). |
| 5 | TAN/BLK | 464 | Delivered Torque Signal (NW7) | Keep Drive-by-wire link to the separate throttle control (TAC) module. Keep only if you run that TAC module; not used with a cable throttle. |
| 6 | RED/BLK | 1228 | PC Solenoid Valve High Control (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 8 | LT BLU/WHT | 1229 | PC Solenoid Valve Low Control (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 9 | DK GRN/WHT | 465 | Fuel Pump Relay Control - Primary | Wire to car Fuel pump relay control. Keep: wire it to the pump relay coil (secondary is for dual-tank trucks). |
| 10 | WHT | 121 | Engine Speed Signal | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. |
| 14 | RED/BLK | 380 | A/C Refrigerant Pressure Sensor Signal (A/C) | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 15 | BRN | 25 | Charge Indicator Control | Wire to car Alternator turn-on (L terminal). Needed with the factory alternator; some later trucks route this through a battery-current module instead. |
| 16 | GRY/BLK | 1694 | 4WD Low Signal | Optional Optional 4WD input. Keep only with the factory transfer case and axle switches. |
| 18 | DK GRN | 1433 | Clutch Start Switch Signal (M/T) | Wire to car Clutch switch (manual transmission). |
| 19 | BLK/WHT | 1695 | Axle Switch Signal (NP2) | Optional Optional 4WD input. Keep only with the factory transfer case and axle switches. |
| 20 | LT GRN/BLK | 822 | VSS Low Signal | Keep Speed sensor input. Keep: the computer needs vehicle speed. |
| 21 | PPL/WHT | 821 | VSS High Signal | Keep Speed sensor input. Keep: the computer needs vehicle speed. |
| 22 | RED/BLK | 1230 | AT ISS High Signal (4WD w/MT1) | Auto trans 4L80E input shaft speed (or a 4WD transfer-case speed input on some trucks). Keep with a 4L80E. |
| 23 | DK BLU/WHT | 1231 | AT ISS Low Signal (4WD w/MT1) | Auto trans 4L80E input shaft speed (or a 4WD transfer-case speed input on some trucks). Keep with a 4L80E. |
| 24 | DK BLU | – | Throttle Position Sensor Signal - TPS Pin C - Cable Throttle ONLY | Keep Cable-throttle P59s only (throttle position sensor). Not used with drive-by-wire. |
| 25 | TAN | 472 | IAT Sensor Signal | Keep Engine sensor or output. Keep. |
| 26 | PPL | 2121 | IC 1 Control | Keep Engine sensor or output. Keep. |
| 27 | RED | 2127 | IC 7 Control | Keep Engine sensor or output. Keep. |
| 28 | LT BLU/WHT | 2126 | IC 6 Control | Keep Engine sensor or output. Keep. |
| 29 | DK GRN/WHT | 2124 | IC 4 Control | Keep Engine sensor or output. Keep. |
| 31 | YEL | 492 | MAF Sensor Signal | Keep Engine sensor or output. Keep. |
| 32 | LT GRN | 432 | MAP Sensor Signal | Keep Engine sensor or output. Keep. |
| 33 | – | – | Empty cavity | Wire to car Empty from the factory. Add a terminal here for fan 2 relay control. |
| 34 | DK GRN/WHT | 428 | EVAP Canister Purge Solenoid Control | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 39 | RED | 631 | 12 Volt Reference (CMP) | Keep Engine sensor or output. Keep. |
| 40 | BLK/WHT | 451 | PCM Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 42 | TAN/BLK | 422 | TCC Solenoid Valve Control (M30/M32) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 43 | DK GRN/WHT | 459 | A/C Compressor Clutch Relay Control (A/C) | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 45 | WHT | 1310 | EVAP Canister Vent Solenoid Control (EVA) | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 46 | BRN/WHT | 419 | Check Engine Light Control | Wire to car Check-engine light. Run to a dash light. |
| 47 | YEL/BLK | 1223 | 2-3 Shift Solenoid Valve Control (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 48 | LT GRN | 1222 | 1-2 Shift Solenoid Valve Control (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 49 | YEL/BLK | 1827 | Vehicle Speed Signal OUT 129k/mile | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. |
| 50 | DK GRN/WHT | 817 | Vehicle Speed Signal OUT 4k/mile | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. |
| 51 | YEL/BLK | 1227 | TFT Sensor Signal (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 52 | BRN | 2391 | HO2S Heater Low Control Bank 1 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 53 | RED/WHT | 3223 | HO2S Heater Low Control Bank 2 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 54 | PPL | 1589 | Fuel Level Sensor Signal - Primary | Optional Optional input. Keep only if you use that feature or gauge. |
| 57 | BLK | 552 | Low Reference (IAT) | Keep Engine sensor or output. Keep. |
| 58 | TAN/WHT | 332 | Oil Pressure Sensor Signal | Keep Engine sensor or output. Keep. |
| 59 | PPL | 806 | Crank Voltage | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 60 | BRN | 2129 | Ignition Control Reference Low Bank 1 | Keep Engine sensor or output. Keep. |
| 61 | BRN/WHT | 2130 | Ignition Control Reference Low Bank 2 | Keep Engine sensor or output. Keep. |
| 62 | GRY | 773 | Transmission Range Switch Signal C (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 63 | PNK | 1224 | Transmission Fluid Pressure Switch Signal A (A/T) | Auto trans Automatic transmission (4L60E/4L80E). Keep with a computer-controlled automatic; not needed with a manual or a non-electronic automatic. |
| 64 | DK GRN | 890 | Fuel Tank Pressure Sensor Signal (EVA) | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 66 | PPL/WHT | 2128 | IC 8 Control | Keep Engine sensor or output. Keep. |
| 67 | RED/WHT | 2122 | IC 2 Control | Keep Engine sensor or output. Keep. |
| 68 | DK GRN | 2125 | IC 5 Control | Keep Engine sensor or output. Keep. |
| 69 | LT BLU | 2123 | IC 3 Control | Keep Engine sensor or output. Keep. |
| 72 | BLK/WHT | 3113 | HO2S Heater Low Control Bank 1 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 73 | DK BLU | 1936 | Fuel Level Sensor Signal - Secondary | Optional Optional input. Keep only if you use that feature or gauge. |
| 74 | LT GRN | 3212 | HO2S Heater Low Control Bank 2 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 75 | GRY | 23 | Generator Field Duty Cycle Signal | Wire to car Alternator control. Keep with a factory computer-controlled alternator. |
| 80 | BLK | 2751 | Low Reference (A/C) | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
E38, Gen IV (X1 73-pin + X2 80-pin)
The Gen IV E38 (2007-on trucks, G8, Camaro and others with 58x reluctor engines). The E38 runs the engine only; a 6L80 or 4L60E behind it is shifted by a separate transmission computer. This is the full list of E38 circuits; rows marked "not populated on every harness" only exist with certain options.
E38: connector X1 (73-pin)
| Pin | Wire | Circuit | Function | Standalone harness |
|---|---|---|---|---|
| 1 | ORN/BLK | 1786 | Park/Neutral Switch Signal | Auto trans Park/neutral signal from the transmission range switch. Needed for starting and idle control with an automatic. The E38 does not shift the transmission; a separate transmission computer does. |
| 2 | GRY/BLK | 1694 | 4WD Low Switch Signal | Optional Optional 4WD input. Keep only with the factory transfer case and axle switches. |
| 3 | TAN/WHT | 1695 | 4WD Mode/2Sp Axle/Brake Switch B Signal | Optional Optional 4WD input. Keep only with the factory transfer case and axle switches. |
| 4 | PPL/WHT | 1035 | Starter Relay Coil Supply Voltage | Wire to car Starter relay control (on some vehicles only). Not populated on every harness (option-dependent). |
| 6 | GRY | 48 | Clutch Pedal Switch B Signal | Wire to car Clutch switch (manual transmission). Not populated on every harness (option-dependent). |
| 9 | LT BLU/WHT | 6311 | Brake Switch Signal | Wire to car Brake switch. 12 V with the pedal pressed. Needed for converter lockup, cruise and drive-by-wire. |
| 10 | PPL/WHT | 1668 | HO2S High Signal - Bank 1 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 11 | TAN/WHT | 1669 | HO2S Low Signal - Bank 1 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 12 | ORN/BLK | 380 | A/C Refrigerant Pressure Sensor Signal | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 13 | TAN | 5514 | Low Reference (ACP) | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 14 | PPL/WHT | 5024 | Low Reference - Tach Return | Wire to car Tach signal return. Use it with the tach output if your gauge needs it. Not populated on every harness (option-dependent). |
| 16 | PPL | 1589 | Fuel Level Sensor Signal - Primary | Optional Optional input. Keep only if you use that feature or gauge. |
| 17 | DK BLU/WHT | 473 | High Speed Cooling Fan Relay Control | Wire to car Cooling fan relay. The computer grounds it to turn the fan on. Not populated on every harness (option-dependent). |
| 18 | DK BLU | 5985 | Accessory Wakeup Serial Data | Wire to car Data line. Run the OBD-II one to the diagnostic port so you can scan and flash. Others go to factory modules you may not keep. |
| 19 | PNK | 439 | Ignition 1 Voltage | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 20 | RED/WHT | 440 | Battery Positive Voltage | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 23 | PPL | 1272 | Low Reference (APP2) | Keep Gas pedal (drive-by-wire). Keep with a DBW pedal. |
| 24 | DK GRN | 890 | Fuel Tank Pressure Sensor Signal | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 25 | BRN | 846 | AIR Pump Relay Control | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. Not populated on every harness (option-dependent). |
| 26 | DK BLU | 6306 | Clutch Pedal Position Sensor Signal | Wire to car Clutch switch (manual transmission). Not populated on every harness (option-dependent). |
| 27 | TAN/BLK | 2501 | High Speed GMLAN Serial Data Bus (-) | Wire to car Data line. Run the OBD-II one to the diagnostic port so you can scan and flash. Others go to factory modules you may not keep. |
| 28 | TAN/BLK | 2500 | High Speed GMLAN Serial Data Bus (+) | Wire to car Data line. Run the OBD-II one to the diagnostic port so you can scan and flash. Others go to factory modules you may not keep. |
| 29 | DK BLU | 1161 | APP Sensor 1 Signal | Keep Gas pedal (drive-by-wire). Keep with a DBW pedal. |
| 30 | BRN | 1271 | Low Reference (APP1) | Keep Gas pedal (drive-by-wire). Keep with a DBW pedal. |
| 31 | TAN/BLK | 6049 | Low Reference (FTP, Fuel Level) | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 32 | LT BLU | 1162 | APP Sensor 2 Signal | Keep Gas pedal (drive-by-wire). Keep with a DBW pedal. |
| 33 | GRY | 2709 | 5-Volt Reference 1 (FTP) | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 34 | GRY/WHT | 2700 | 5-Volt Reference 1 (ACP) | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 35 | TAN | 2760 | 5-Volt Reference 1 | Keep Engine sensor or output. Keep. Not populated on every harness (option-dependent). |
| 36 | TAN | 1274 | 5-Volt Reference 1 (APP2) | Keep Gas pedal (drive-by-wire). Keep with a DBW pedal. |
| 37 | TAN/BLK | 472 | IAT Sensor Signal | Keep Engine sensor or output. Keep. |
| 38 | TAN | 2760 | Low Reference (IAT) | Keep Engine sensor or output. Keep. Check: Circuit number repeats pin X1-35 in our source list; check the wire color on your harness. |
| 41 | YEL | 492 | MAF Sensor Signal | Keep Engine sensor or output. Keep. |
| 42 | DK GRN/WHT | 6294 | Low Reference (CPP) | Wire to car Clutch switch (manual transmission). Not populated on every harness (option-dependent). |
| 47 | PNK/BLK | 1339 | Ignition 1 (Powertrain Relay) Voltage | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
| 48 | WHT/BLK | 5039 | Tach Signal | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. Not populated on every harness (option-dependent). |
| 49 | TAN | 1671 | HO2S Low Signal - Bank 2 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 50 | DK GRN/WHT | 465 | Fuel Pump Relay Control - Primary | Wire to car Fuel pump relay control. Keep: wire it to the pump relay coil (secondary is for dual-tank trucks). |
| 51 | TAN | 1465 | Fuel Pump Relay Control - Secondary | Wire to car Fuel pump relay control. Keep: wire it to the pump relay coil (secondary is for dual-tank trucks). |
| 52 | YEL/BLK | 625 | Starter Enable Relay Control (HSD) | Wire to car Starter relay control (on some vehicles only). |
| 54 | DK GRN | 6293 | 5-Volt Reference 2 (CPP) | Wire to car Clutch switch (manual transmission). Not populated on every harness (option-dependent). |
| 56 | WHT/BLK | 1164 | 5-Volt Reference 2 (APP1) | Keep Gas pedal (drive-by-wire). Keep with a DBW pedal. |
| 57 | YEL/BLK | 1827 | Vehicle Speed Signal | Wire to car Output to your speedometer or tachometer. Run it to the gauge if it takes this signal. |
| 58 | DK GRN | 335 | Low Speed Cooling Fan Relay Control | Wire to car Cooling fan relay. The computer grounds it to turn the fan on. |
| 59 | YEL | 5991 | Powertrain Relay Coil Control | Keep Powertrain relay control. The computer switches this relay to feed the injectors, coils and sensors. Keep. |
| 61 | WHT | 1310 | EVAP Canister Vent Solenoid Control | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 63 | DK GRN/WHT | 459 | A/C Compressor Clutch Relay Control | Wire to car A/C. Keep only if the computer will control the A/C compressor. |
| 64 | ORN/WHT | 3223 | HO2S Heater Low Control - Bank 2 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 65 | GRY/WHT | 3122 | HO2S Heater Low Control - Bank 1 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 66 | GRY | 587 | Skip Shift Solenoid/Fan 3/EBPV Control | Optional AFM solenoid on AFM engines, or the manual-transmission reverse lockout / skip-shift solenoid, depending on the calibration. Not populated on every harness (option-dependent). |
| 67 | YEL/BLK | 625 | Starter Enable Relay Control (LSD) | Wire to car Starter relay control (on some vehicles only). Not populated on every harness (option-dependent). |
| 68 | BRN/WHT | 419 | MIL Control | Wire to car Check-engine light. Run to a dash light. |
| 69 | PPL | 1670 | HO2S High Signal - Bank 2 Sensor 2 | Optional Rear (downstream) O2 sensor or its heater. Can be removed only if your state doesn't require it, and the tune must turn off the rear O2 tests. |
| 70 | LT BLU | 1937 | Fuel Level Sensor Signal - Secondary | Optional Optional input. Keep only if you use that feature or gauge. |
| 71 | PPL/WHT | 821 | Vehicle Speed Sensor (VSS) High Signal | Keep Speed sensor input. Keep: the computer needs vehicle speed. Check: Some trucks use this pin for a copied transmission output speed signal (circuit 6399) instead. |
| 72 | LT GRN/BLK | 822 | Vehicle Speed Sensor (VSS) Low Signal | Keep Speed sensor input. Keep: the computer needs vehicle speed. |
| 73 | BLK/WHT | 451 | Ground | Keep Power or ground. Wire it to fused battery power, key-on power or a clean engine ground as labeled. |
E38: connector X2 (80-pin)
| Pin | Wire | Circuit | Function | Standalone harness |
|---|---|---|---|---|
| 1 | GRY | 474 | 5-Volt Reference 2 (AIR) | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. Not populated on every harness (option-dependent). |
| 2 | PPL/WHT | 6270 | 5-Volt Reference 2 (CKP) | Keep Engine sensor or output. Keep. |
| 3 | GRY | 2701 | 5-Volt Reference 2 (TPS) | Keep Engine sensor or output. Keep. |
| 5 | BRN | 582 | TAC Motor Control - 2 | Keep Engine sensor or output. Keep. |
| 6 | YEL | 581 | TAC Motor Control - 1 | Keep Engine sensor or output. Keep. |
| 7 | PNK/BLK | 429 | AIR Solenoid Relay Control | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. Not populated on every harness (option-dependent). |
| 8 | DK GRN/WHT | 428 | EVAP Canister Purge Solenoid Control | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. |
| 9 | GRY | 5493 | Cylinder Shutoff Solenoid Control (3) | Optional AFM/DOD lifter oil manifold. Not needed if AFM is deleted (tune must turn it off). |
| 10 | DK BLU | 5491 | Cylinder Shutoff Solenoid Control (1) | Optional AFM/DOD lifter oil manifold. Not needed if AFM is deleted (tune must turn it off). |
| 11 | ORN | 5494 | Cylinder Shutoff Solenoid Control (4)/Reverse Lockout Solenoid Control | Optional AFM solenoid on AFM engines, or the manual-transmission reverse lockout / skip-shift solenoid, depending on the calibration. |
| 12 | GRY/WHT | 3113 | HO2S Heater Low Control - Bank 1 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 13 | LT GRN | 3212 | HO2S Heater Low Control - Bank 2 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 14 | LT GRN/BLK | 5492 | Cylinder Shutoff Solenoid Control (2) | Optional AFM/DOD lifter oil manifold. Not needed if AFM is deleted (tune must turn it off). |
| 16 | PPL | 5284 | Camshaft Actuator Solenoid A Control | Keep Engine sensor or output. Keep. |
| 17 | DK BLU/WHT | 878 | Fuel Injector 8 Control | Keep Engine sensor or output. Keep. |
| 18 | TAN/WHT | 845 | Fuel Injector 5 Control | Keep Engine sensor or output. Keep. |
| 19 | YEL/BLK | 846 | Fuel Injector 6 Control | Keep Engine sensor or output. Keep. |
| 20 | TAN | 1744 | Fuel Injector 1 Control | Keep Engine sensor or output. Keep. |
| 21 | YEL | 410 | ECT Sensor Signal | Keep Engine sensor or output. Keep. |
| 22 | TAN | 2761 | Low Reference (ECT) | Keep Engine sensor or output. Keep. |
| 23 | TAN/WHT | 585 | EOT/TFT Sensor Signal | Optional Engine oil or transmission fluid temperature input, depending on the calibration. Optional. Not populated on every harness (option-dependent). |
| 24 | ORN/BLK | 586 | Low Reference (EOT/TFT) | Optional Engine oil or transmission fluid temperature input, depending on the calibration. Optional. Not populated on every harness (option-dependent). |
| 26 | DK BLU | 496 | Knock sensor 1 Signal | Keep Engine sensor or output. Keep. |
| 27 | GRY | 1716 | Knock sensor 1 Signal | Keep Engine sensor or output. Keep. |
| 29 | LT BLU | 1876 | Knock sensor 2 Signal | Keep Engine sensor or output. Keep. |
| 30 | GRY | 2303 | Knock sensor 2 Signal | Keep Engine sensor or output. Keep. |
| 32 | GRY | 23 | Generator Field Duty Cycle Signal (F-Term) | Wire to car Alternator control. Keep with a factory computer-controlled alternator. |
| 33 | BRN | 1174 | Oil Level Switch/Oil Level-Temp Sensor Signal | Optional Optional input. Keep only if you use that feature or gauge. |
| 34 | BLK | 2755 | Low Reference (EOP) | Keep Engine sensor or output. Keep. |
| 35 | TAN | 2752 | Low Reference (TPS) | Keep Engine sensor or output. Keep. |
| 37 | LT GRN/BLK | 1745 | Fuel Injector 2 Control | Keep Engine sensor or output. Keep. |
| 38 | PNK/BLK | 1746 | Fuel Injector 3 Control | Keep Engine sensor or output. Keep. |
| 39 | LT BLU/BLK | 844 | Fuel Injector 4 Control | Keep Engine sensor or output. Keep. |
| 40 | ORN/BLK | 877 | Fuel Injector 7 Control | Keep Engine sensor or output. Keep. |
| 41 | GRY/WHT | 2705 | 5-Volt Reference 1 (EOP) | Keep Engine sensor or output. Keep. |
| 43 | GRY | 2704 | 5-Volt Reference 1 (MAP) | Keep Engine sensor or output. Keep. |
| 44 | DK BLU | 6259 | 5-Volt Reference 1 (CMPA) | Keep Engine sensor or output. Keep. |
| 50 | TAN/WHT | 331 | Oil Pressure Sensor Signal | Keep Engine sensor or output. Keep. |
| 51 | TAN | 476 | Low Reference (AIR) | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. Not populated on every harness (option-dependent). |
| 52 | TAN | 2199 | Low Reference - Camshaft Actuator Solenoid A Return | Keep Engine sensor or output. Keep. |
| 53 | ORN/BLK | 469 | Low Reference (MAP) | Keep Engine sensor or output. Keep. |
| 56 | TAN | 1664 | HO2S Low Signal - Bank 1 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 57 | PPL/WHT | 1665 | HO2S High Signal - Bank 1 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 58 | LT GRN | 432 | MAP Sensor Signal | Keep Engine sensor or output. Keep. |
| 59 | PPL | 1666 | HO2S High Signal - Bank 2 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 60 | TAN | 1667 | HO2S Low Signal - Bank 2 Sensor 1 | Keep Front (upstream) O2 sensor or its heater. Keep: the computer uses these for fuel control. |
| 61 | BRN | 25 | Charge Indicator Signal (L-Term) | Wire to car Alternator control. Keep with a factory computer-controlled alternator. |
| 63 | PPL | 486 | TP Sensor 2 Signal | Keep Engine sensor or output. Keep. |
| 64 | DK BLU/WHT | 6265 | CMP Sensor A Signal | Keep Engine sensor or output. Keep. |
| 65 | DK GRN | 485 | TP Sensor 1 Signal | Keep Engine sensor or output. Keep. |
| 66 | BRN | 6266 | Low Reference (CMPA) | Keep Engine sensor or output. Keep. |
| 67 | WHT | 5268 | AIR Pressure Sensor Signal - Bank 1 | Optional Emissions part (EVAP, EGR or air pump). Remove only where emissions rules allow, and turn off the related tests in the tune. Not populated on every harness (option-dependent). |
| 68 | WHT/BLK | 6271 | CKP Sensor Signal | Keep Engine sensor or output. Keep. |
| 69 | GRY/BLK | 6272 | Low Reference (CKP) | Keep Engine sensor or output. Keep. |
| 70 | PPL | 2121 | IC 1 Control | Keep Engine sensor or output. Keep. |
| 71 | PPL/WHT | 2128 | IC 8 Control | Keep Engine sensor or output. Keep. |
| 72 | ORN | 2127 | IC 7 Control | Keep Engine sensor or output. Keep. |
| 73 | ORN/WHT | 2122 | IC 2 Control | Keep Engine sensor or output. Keep. |
| 74 | LT BLU/WHT | 2126 | IC 6 Control | Keep Engine sensor or output. Keep. |
| 75 | DK GRN | 2125 | IC 5 Control | Keep Engine sensor or output. Keep. |
| 76 | DK GRN/WHT | 2124 | IC 4 Control | Keep Engine sensor or output. Keep. |
| 77 | LT BLU | 2123 | IC 3 Control | Keep Engine sensor or output. Keep. |
| 78 | BRN | 2129 | Low Reference - IC Return | Keep Engine sensor or output. Keep. |
| 79 | BRN/WHT | 2130 | Low Reference - IC Return | Keep Engine sensor or output. Keep. |
Minimum standalone wiring
Whatever the computer, a trimmed factory harness needs these connections to the car:
- Constant battery power (fused) and key-on power to the computer, plus every computer ground to a clean engine ground.
- Fuel pump relay control to the relay coil, with the relay powering the pump through its own fuse.
- OBD-II port: the serial data line, power and grounds, so you can scan and flash it.
- Check-engine light and tach outputs to your gauges, and a vehicle speed sensor input.
- Fan relay control for electric fans (or wire the fans to a separate thermostatic switch).
- With drive-by-wire: the pedal and throttle body (or TAC module) wiring. With an automatic: the transmission pins and a brake switch input.
Prefer a ready-made harness? Compare options in the LS swap ECU comparison, or see the Painless 60522 and Speartech hookup guides. Holley ECU? Holley EFI pinout. Tune basics: swap tune checklist.
How we checked: every P01/P59 row matches across two separately published pin lists. More than 40 pins (power, grounds, crank sensor, transmission, fuel pump, fan, A/C, flex fuel) were also checked against factory pinout reprints and wiring write-ups from other publishers; one circuit number differs between sources and is marked. For the E38, 100 pins match exactly between two published lists. Two pins differ and are marked, and options that one list leaves out are flagged. A 1998–2000 "black box" to 0411 conversion table was left out because it disagreed with the other sources on injector pins.
Sources
- 2005 PCM Pinouts (C1/C2 connector end views) — PerformanceTrucks.net (factory PCM pinout reprint)
- 2001 Silverado PCM Pinout Diagram (factory pinout reprint) — GM factory pinout (via Scribd)
- https://sites.google.com/site/sloppywiki/everything-ls/cheap-stand-alone-trans-controller — Sloppy Mechanics
- Controlling LS1 Fans — Bimmerforums
- E85 Conversion (forum thread) — HP Tuners forum
- 1999 to 2002 Vortec PCM pinouts (C1 blue / C2 red) — LT1 Swap
- 2004 Vortec PCM pinouts (C1 blue / C2 green) — LT1 Swap
- Standalone pinout: 1999 5.3 truck, connector C1 (blue) — Ewalt's Auto Tuning
- Standalone pinout: 1999 5.3 truck, connector C2 (red) — Ewalt's Auto Tuning
- Standalone pinout: 2004 4.8/5.3/6.0 truck, connector C1 (blue) — Ewalt's Auto Tuning
- Standalone pinout: 2004 4.8/5.3/6.0 truck, connector C2 (green) — Ewalt's Auto Tuning
- E38 ECM connector pinouts (2008 5.3 truck harness) — LT1 Swap
- E38 complete pinout — TorqueUp