[Prp77]

Posting as it might help others when tracking down an electrical issue that ended up being the RDC module. My research on multiple threads, youtube videos etc pointed to the RDC module being at least a possible suspect.

The car: 2011 e90 328i RWD manual, aprox 90k miles. 2 weeks ago I got a random ABS/TDC error while leaving a stop sign. I was not accelerating hard, no way a tire lost traction.

Next day 50 mile drive to work. All is good. Went to start up car for drive home. Dash started going crazy. Every warning light was on. Engine was idling fine, but tach and gas gauge kept bouncing to zero for a second multiple times.

Shut the car off, restarted and now just the TPMS light is on with the message ("Inactive"). All tires had adequate pressure, appeared to be problem with the TPMS system. On the way home TPMS light kept going on and off...probably 20 times in the 50 mile commute.

Once home using a handheld voltmeter and then the hidden one on the dash battery seamed ok...not fantastic, but ok. 12.2 volts at rest, 13.9 while running. But
when turning on accessory mode (engine not running) voltage would immediately drop to 11.9. The dash freaked out again on another start up while trying to diagnose. Some warning lights were still on. So at this point thinking it might be the battery.

I disconnected the RDC module (behind the rear tire on right side). Dash no longer "freaked out", but still number of warning lights were on including "Service Engine Soon" light, and for whatever reason the dreaded "tamper dot" showed up on the odometer. Ugh.

Next step was that I bought the bimmergeeks Protool diagnostic and coding software and set it up on a Amazon Fire tablet.

Fast forward a few days...initial read of codes looked like a nightmare. So many issues didn't know where to start.

I plugged the RDC module back in and reset the codes. The reader would then instantly report new codes (usually 4 of them), but when resetting again different codes would appear.

With nothing to lose I unplugged the RDC module. Reset the codes and... magic? no more codes. Tamper dot gone as well.

I have since used the coder to disable TPMS. I will eventually code in the FTM (flat tire monitoring) functionality.

No more warning lights...all is good again.

I feel I got very lucky and did not have to do very much diagnosing at all. Apparently the failure of the RDC module is common. Common enough that it was the first thing I disconnected.

If you experience similar issues (multiple codes, dash doing crazy things), you could probably do worse than suspecting the RDC module and starting there.

[jim04011]

Originally Posted by Prp77

Posting as it might help others when tracking down an electrical issue that ended up being the RDC module. My research on multiple threads, youtube videos etc pointed to the RDC module being at least a possible suspect.

The car: 2011 e90 328i RWD manual, aprox 90k miles. 2 weeks ago I got a random ABS/TDC error while leaving a stop sign. I was not accelerating hard, no way a tire lost traction.

Next day 50 mile drive to work. All is good. Went to start up car for drive home. Dash started going crazy. Every warning light was on. Engine was idling fine, but tach and gas gauge kept bouncing to zero for a second multiple times.

Shut the car off, restarted and now just the TPMS light is on with the message ("Inactive"). All tires had adequate pressure, appeared to be problem with the TPMS system. On the way home TPMS light kept going on and off...probably 20 times in the 50 mile commute.

Once home using a handheld voltmeter and then the hidden one on the dash battery seamed ok...not fantastic, but ok. 12.2 volts at rest, 13.9 while running. But
when turning on accessory mode (engine not running) voltage would immediately drop to 11.9. The dash freaked out again on another start up while trying to diagnose. Some warning lights were still on. So at this point thinking it might be the battery.

I disconnected the RDC module (behind the rear tire on right side). Dash no longer "freaked out", but still number of warning lights were on including "Service Engine Soon" light, and for whatever reason the dreaded "tamper dot" showed up on the odometer. Ugh.

Next step was that I bought the bimmergeeks Protool diagnostic and coding software and set it up on a Amazon Fire tablet.

Fast forward a few days...initial read of codes looked like a nightmare. So many issues didn't know where to start.

I plugged the RDC module back in and reset the codes. The reader would then instantly report new codes (usually 4 of them), but when resetting again different codes would appear.

With nothing to lose I unplugged the RDC module. Reset the codes and... magic? no more codes. Tamper dot gone as well.

I have since used the coder to disable TPMS. I will eventually code in the FTM (flat tire monitoring) functionality.

No more warning lights...all is good again.

I feel I got very lucky and did not have to do very much diagnosing at all. Apparently the failure of the RDC module is common. Common enough that it was the first thing I disconnected.

If you experience similar issues (multiple codes, dash doing crazy things), you could probably do worse than suspecting the RDC module and starting there.

Hi, my 2011 328i xDrive is doing exactly the same stuff -- dash lights up, tach bounces, general mayhem. I'll unplug the RDC module this weekend. How do you "use the coder to disable TPMS"? I have a BluDriver dongle and a Foxwell tool.

Thanks!

[Mike K]

I had the same issue as the OP. Also 2011 RWD. I took out the RDC and all was normal other than the TPMS code. I floated the RDC in a sink full of water and it floated and didn't leak. It turned out I just needed to waterproof the RDC plug connection with some electrical tape. Why they but that thing right where water splashes I'll never understand?