Phantom_9192

Supercharged 2006 S2k race car (not remotely streetable) with 5 speed dog box. I bought it recently and the ABS isn't working (I squared off a Hoosier my first session out... ugh), Seller said they never completely sorted out the trans swap to their liking but everything else was built to the nines and well-sorted.
Multiple codes, but the problem seems to be in the LR. In my data, I could see the LR speed spiking/dropping at over around 110 MPH.
After much diagnosis, we still can't tell exactly what's going on.
Here are the highlights of where we stand.
First issue: RockAuto Standard part number ALS1567 is clearly labeled as rear left but when you go to install it, it's clearly set up for the right rear based on the mounting plates. It also doesn't read the same during wheel speed and pulser tests as the original left rear sensor. I'm returning it and ordering a right rear which looks in the pictures like the correct one for the LR. I would think the left and right rear sensors should be identical except for the mounting plates, correct?

Using a tester, we have tested the pulser (tone ring) and the wheel speed. We've tested the left rear wheel connected both to the left rear and right rear connectors with the same results, so it seems to be in the left rear wheel well somewhere (sensor down). Tone ring looks good and gap is identical to right rear (which works well).
Pulser test does not go well. It requires a strong spin of the wheel to read, much more so than any other corner.

So at this point having been through wiring and all sorts of stuff, I'm going to try a "right rear" sensor (which appears to be correct for the left rear of the car) from RockAuto since I can't seem to find the correct one in short order anywhere else.

Any thoughts as to what else we can try? The car is pretty disappointing to drive at 10/10th's with the stock bias and no abs, as you can imagine. I'd estimate 2 seconds per lap as it stands after my first two sessions on track (~2:05 lap time).
TIA!

Jub

Are you running a factory ECU or something different? Do you have a functioning speedometer and is it stock dash?

I seem to remember something about the vehicle speed sensor (VSS) in a S2k being part of the transmission and being difficult to deal with for transmission swaps. I don't know the details on that but I know others have run across that issue. I'm also not knowledgeable to know if that sensor is needed for ABS.

06+ ABS requires more inputs than the 00-05 ABS and I don't know the ins and outs of the system. I think that you need to be running a factory ECU for one but I'm not completely clear on that. One thing I do know is that highly built 06+ cars often retrofit an 00-05 ABS system into the car because the 00-05 system runs as a standalone as far as I understand. I believe the 04-05 is a little bit more advanced than the 00-03 but I can't elaborate on that. Worst case scenario, if fixing yours is nothing simple, you could retrofit one of the older ABS models.

B serious

Its likely an wheel speed sensor. If it doesn't fit correctly, it won't read correctly.

See if a part which fits correctly will solve your problem.

Make sure the hall effect ring on the axle is OK.

Also, don't trust aftermarket sensors. If the problem persists with a new aftermarket sensor, try a good used OEM sensor before moving on.