What sensor and wiring differences are there when swapping an LS2 in place of an LS1?
A Gen IV engine differs from Gen III in the sensors the PCM reads: a 58x crank reluctor with a gray crank sensor (Gen III: 24x, black), a 4x cam sensor on the front timing cover (Gen III: 1x, at the rear of the block), EV6-style injectors with USCAR connectors, and drive-by-wire throttle. Many also have AFM and/or VVT. So a Gen III PCM and harness won't run it directly. Use a Gen IV PCM and harness (or a 58x-capable aftermarket ECU), add a DBW pedal, and plan an AFM delete if you're changing the cam.
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The main differences are the cam sensor, the knock sensors and the valley cover. On Gen III the cam sensor is at the back of the block by the oil pressure sender, while Gen IV puts it in the front timing cover with a 1x cam gear, so you'll need the Gen IV cover, sensor and a harness extension. Knock sensors move from the valley to the pan rails; the larger Gen III-style sensors need drilled and tapped bosses on the Gen IV block plus a knock-sensor harness extension, and you'll need an LS2/LS3 valley cover because the Gen III one won't fit.
Check this first:
- Verify the LS2 has a 24x reluctor if you want to keep your Gen III electronics
- Plan for cam and knock sensor harness extensions
Based on what we've seen work across our own builds, our friends' builds and the wider LS community, reviewed by our lead shop tuner (over 20 years of LS and LT tuning experience). Every combination is different, so use at your own risk.
Go deeper
Check this first
- Decide: 24x conversion (keep 98 PCM) or full 58x/E40 swap
- Knock sensor and cam sensor wiring plan
Try this, then this
- Keep the 98 PCM with a 24x conversion — keeps the car plug-and-play. Worked if: reluctor converted and sensors extended
How you know it's fixed
- Engine runs on chosen electronics with all sensors reading
Still not fixed?
- LS2's 58x reluctor will not talk to the 98 PCM without a conversion box
Key numbers
| What | Value |
|---|---|
| LS2 differences from LS1 | 58x reluctor, front cam sensor, DBW throttle |
Every option we know of
| Maker / product | Part # | Fits | Price | Where | Status / notes |
|---|---|---|---|---|---|
| Lingenfelter 58x to 24x conversion module | n/a | LS2/LS3 into 24x cars | about $300 | retail | In production wiring required |
Prices are approximate as of September 2026. We list every option we know of, including small shops and used parts we can't link to. Confirm fitment with the seller.
Time and cost: A weekend plus wiring