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Which diagnostic trouble codes should be turned off in an LS swap tune?

What a swap calibration typically handles (GM Truck Central, Warr Performance, Chevy Hardcore):

  • VATS/anti-theft disabled: the recipient vehicle doesn't have the matching theft hardware.
  • Diagnostics matched to the hardware: rear O2 and catalyst, EGR, canister purge, fuel-tank pressure, and alternator codes the swap harness doesn't wire.
  • Correct VIN, electric-fan temperatures set, and the speed limiter raised on retailer-programmed units.
  • Engine and driveline data: injector flow, VE, spark, axle ratio, and whether EGR, EVAP and secondary air are present.

Rule of thumb: disable only the codes for hardware your swap doesn't have. Speedway notes emissions parts can be left out of operation, but the PCM may need programming so it doesn't set codes for them. If you delete the MAF, its codes need reconfiguring too (LSX Magazine). See the swap tune checklist.

More: who tunes it, and how to learn.

Confidence: medium — sources disagree or are limited; check the sources below.

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