Dsc + tpm

[bmw@usatran.com]

I have been reading and doing all the "cheap" things that I can, but so far, the root cause have allured me. However, everything I read is DSC + ABS or DSC + ABS + TPM. Checked and my ABS light do work but it never come ON when my problem appeared.

Vehicle: 2001 BMW E46 M3

Brought the car used. Only thing the previously owner changed out was putting a halo-light in and a new "used" light control module which triggered the tamper dot (which I cleared it with INPA recently). Anyway, I drove the car daily for about a year when the DSC + TPM lights both came ON and stayed ON while driving <30 mph through a neighborhood (first time). I felt the vehicle brake for a split second but everything was normal afterward (beside the two lights illuminated). Pulled off the side of the road and checked the vehicle out to make sure I didn't run over something. When I got back in the car and turn it on, lights no longer ON. Asked the previous owner if he ever had this problem and he said no.

It ran fine for at least 6 months and then it happened again and have been happening even since, randomly. Took it to the BMW dealership in town to have them diagnose it. After scanning the vehicle, they said it was the steering angle sensor. Brought the part from them (wanted to make sure they can't said I didn't use an OEM part) and installed it myself and took the car back to them for programming. Five minute after driving off the BMW lot, the two lights came back ON. (NOT CHEAP)

After that, I replaced all 4 wheel speed sensors, the yaw sensor underneath the driver seat (actually, I replaced the driver seat itself with one from another running M3 which I help removed) and cleaned the connector to the ABS module.

Just this week, I contacted a company that does ABS module rebuilding and described my problem to them. They said they are pretty sure that it is not the ABS module causing this problem and suggested replacing the speed sensors and possibly the tone ring (I'm assuming that is the same as the reluctor ring).

Again, the problem (DSC + TPM lights) come on randomly (doesn't matter if I was going slow or fast, how far I drive, or even if the car is moving or not--they had came ON while I'm in Park in a parking lot, with the engine running, waiting on people to do their shopping, no problem getting to the parking lot). I can turn the car/ignition OFF and back ON and the lights and, 98% of the time, the lights will go OFF and they may or may not come back ON the rest of the drive.

One last thing, when they come ON, I can feel the brake being applied (split second if I am going fast and longer the slower I am driving). At slower speed (like less then 30 mph), the DSC light will blinks (feel the brakes while it is blinking). Once it stop blinking and decided to stay ON, the TPM light will come ON at the same time or shortly thereafter. If I start the car and purposely turn off DSC (like I do now), when the TPM light finally come ON, I don't feel any "braking action". The DSC light doesn't blink (when I turn off DSC, the light is turned ON on the dash). I know the problem had occurred because (1) I can no longer turn DSC ON/OFF manually and (2) the TPM light is illuminated.

Anyone had this problem before and what the fix is? Any other suggestion to possible cause?

Thanks in advance.

[dworthy]

Since you do have INPA, what codes are in the DSC?

Also have you replaced tires recently? You would need to go into the DSC and reset the tire threshold measurements.

To reset the steering angle sensor is just raising the car in the air and going lock to lock 5x times with the ignition switch on.

Stop throwing parts at the car without a proper diagnostic.

[bmw@usatran.com]

Thanks for the suggestion on the angle sensor. Will try it even though I already had the BMW dealership re-programmed it after I had it replaced because of their professional diagnose.

As for the yaw sensor, it came with the replacement seat since the old seat was badly ripped. Is there a way to test this sensor as I only assuming it is good since it came out another M3.

I'm on business travel this week so can't try the INPA until this weekend. The last time that I connected INPA to the car showed no code (after I experienced this problem). Maybe I wasn't looking in the right place.

[bmw@usatran.com]

Did the 5x wheel lock to reset the steering angle sensor but did not solve the problem.

I'm trying to get the new install of INPA working. Windows 10 updates killed my virtualbox so I can no longer start the WinXP virtual machine that INPA was installed on. Followed the Win10 install of INPA. Program start fine but when I selected E46, I'm getting error message that it can't compile script. Working through that now.

[dworthy]

Yeah INPA can be troublesome with Win-10 if you are running 64-bit. I keep an old laptop running Win-XP just for this reason alone.

Once you get INPA running, should also be a reset function in there for the steering angle sensor.

Not sure on how to test the yaw sensor, if the codes clears, I would say your good.

[bmw@usatran.com]

Just wanted to close out this post. The problem turned out to be the yaw sensor itself. I was incorrect when I thought that when I swapped the driver seat with one from another running BMW M3, I had swapped the yaw sensor too. The sensor is actually underneath the carpet under the driver seat, not on the seat itself. I found a YouTube video on how to test a yaw sensor with a voltmeter while driving. I didn't get the voltage reading it was supposed to gave so I replaced it and the TPM and DSC lights went away. I brought a used yaw sensor from Ebay (part number 3452-6 754 289) for $60. No re-programming/adaptation required. DSC does work as expected when driving on a recent raining, slippery road. Have been driving with this replacement sensor for about 4 months now without any issue.

[dworthy]

Thank-you for coming back and closing out the thread.

Since then I have found how to use INPA on Win-10 64-bit, and many other things too.