PSM and ABS Cautions on 996

[goldenwarrior1]

While detailing my 02 996 C4S I raised each wheel independently and rotated the wheel back and forth by hand in order to clean the inside of the wheels and clean the brake calipers. When I went to start the car to move it, both the PSM and ABS caution lights immediately came on. If I restart the car they go off but after driving for a few minutes they come right back on. I have driven about 300 miles since this occurred and it continues every time I drive. I wouldn’t think the 4 wheel drive is that sensitive or that by simply rotating a wheel independently would cause this but it has. Do I need to have the dealer reset the system? Did I mess up the calibration? Any help would be greatly appreciated.

Thanks!

[SH-GT3]

Did you do this with the key in the ignition and turned to the first position?

[goldenwarrior1]

Did you do this with the key in the ignition and turned to the first position?

Key was not in ignition.

[SH-GT3]

Perhaps the sensors [don't know where they are located] became misaligned when just one wheel was rotated enough so that the error was triggered. I'd simply call the dealer first and see what they tell you. Seems too coincidental for the error lights to pop up right after the detailing effort.

[goldenwarrior1]

Perhaps the sensors [don't know where they are located] became misaligned when just one wheel was rotated enough so that the error was triggered. I'd simply call the dealer first and see what they tell you. Seems too coincidental for the error lights to pop up right after the detailing effort.

Wheel sensors are bolted into the hub, way too secure to be disturbed by rotating wheel. I pulled all the wheels and looked at each sensor. Was hoping someone else had a similar experience and would save me a trip to the dealers.

[RFM]

1) The front sensor wiring has a weak point when the wheels are hanging free on the suspension, the INSIDE wiring will break between the attachment grommet, (on the shock absorber) and the wheel well cause the infinitely many up and downwards movements of the wheels during the years of driving.

2) Check the brake switch.

3) Check the MAF.

[goldenwarrior1]

1) The front sensor wiring has a weak point when the wheels are hanging free on the suspension, the INSIDE wiring will break between the attachment grommet, (on the shock absorber) and the wheel well cause the infinitely many up and downwards movements of the wheels during the years of driving.

2) Check the brake switch.

3) Check the MAF.

That makes sense, I will check the wiring. Not sure what the MAF has to do with the ABS though??? I saw that on another thread. Assuming MAF = Mass Air Flow sensor!

Thanks!

[RFM]

Brake switch, MAF and throttle body affect ABS and TC.

[goldenwarrior1]

Brake switch, MAF and throttle body affect ABS and TC.

Interseting, then perhaps that could also be causing my P0430 code that popped within a day prior to that! Just assumed it was coincidence and that I had a bad cat!

[goldenwarrior1]

OK, Did some checking; what the normal range is for a MAF sensor on my 2002 996 C4S. My readings are at .94 at idle and about 2.5 lbs/hr at about 2K RPM. Seems low to me. Also, the ABS PSM lights come on when I first touch the brake after I have started moving. Brake switch? Brake lights work?

As always, thanks any advice.