ABS Issue - 2011 128i

[K9Leader]

So, I picked up a 128i as a project car a couple of weeks ago. Not many options - 6MT, slicktop, manual seats (but heated), not Sport or M-Sport. I was looking for something pretty basic - would have liked Sport or M-Sport - but color, other options were just what I wanted and suspension/wheels can be upgraded.

It was bargain-priced because it had ABS warning lights on and TCS (traction control) lights. The seller said it was giving codes for the right rear wheel sensor and that he had replaced that sensor (not clear if he also did the left rear also but when I pulled that one off tonight it looked real clean except for where the reluctor ring had rubbed against the sensor).

I solved the traction control lights and power problems by shimming the right rear sensor out with a washer so that it was not touching or too close to the reluctor ring. That did resolve the traction control issues - well, temporarily, as the long-term fix will be new drive shafts with corrosion free reluctor rings.

Along with the ABS warnings, the speedometer was not working, which pointed me to the left rear sensor, so I replaced that tonight (and shimmed it out with a washer. While the speedometer is working again, the ABS situation is unchanged.

However, there are still codes for the right rear sensor:

002FE6 Vehicle speed, rear wheel speed sensor / right electrically
Last occurred at: 135399 mi

002F57 Vehicle speed signal change
Last occurred at: 135399 mi

002F5F Vehicle speed, plausibility
Last occurred at: 135399 mi

I will change that one out over the weekend and see if that resolves it, but I'm not holding my breath. The 002FE6 code's "right electrically" wording makes me wonder if the problem is somewhere in the wiring to the ABS module, or perhaps at the connection to the ABS module, or inside the ABS module (so repair or replace time).

There are some other codes that puzzle me:

Fault code: 005DE3 DSC-ECU: ECU-internal: status wheel speed sensors of the SP interface does not match the configuration. / Coding wrong / EU-valve 2 / Lining Wear HA reaches critical coating thickness. /
DSC-ECU: ECU-internal: status raddrehzahl sensoroutput the SP interface does not match the configuration. / DSC ECU: ECU internally: status raddrehzahl sensoroutput of SP-interface does not match the configuration --- (DSC: controller internal)
Last occurred at: 12725 mi

Fault code: 005DE2 Coding missing / DSC-ECU: ECU-internal: dePwm status: software / hardware configurations do not match (DF11i / s). / EU-valve 1 / Lining Wear VA reaches critical coating thickness. / DSCECU: ECU-internal: dePwm status: software / hardware configurations do not match; DF11i / s --- (DSC: controller internal)
Last occurred at: 12725 mi

Fault code: 005DC2 Speed sensor pulse wheel rear right periodic monitoring. / Valve USV2: general error. / Valve USV2: general error --- (DSC: control valve actuation device) / Valve (USV2): general error. /
Incorrect wheel speed sensor, rear left
Last occurred at: 10180 mi

These all sound related to the whole wheel speed sensor issues I am having now but they all indicate "last occurred" a long time and many miles ago. Are these just old codes? Or are they somehow related to the current issues?

One other oddity. When I was removing the left rear wheel sensor, I found a tube (with a screw in the end plugging it up) zip-tied to the wheel sensor wire. Is this some sort of drain tube? Why would it be plugged?

[iamroddy]

I cant help out with the codes, but the tube is vacuum piped in from the engine bay. It's used to power the flap in the stock exhaust. Nothing to worry about unless it becomes a leak.
I've done the same with mine, but slid the hose back up into the trunk floor.

[K9Leader]

Originally Posted by iamroddy

I cant help out with the codes, but the tube is vacuum piped in from the engine bay. It's used to power the flap in the stock exhaust. Nothing to worry about unless it becomes a leak.
I've done the same with mine, but slid the hose back up into the trunk floor.

Thanks for the info!

[m_thompson]

I would clear the codes and see if they return. It is common for the ends of the axles to rust and increase the diameter of the reluctor ring which then hits the ABS sensor. This lights ABS, DSC and ASC lights.

One temporary solution is to install a small shim under the ABS sensor mounting screw. This worked for me for two years, but now the lights are back so it is time for a new axle.

[K9Leader]

Originally Posted by m_thompson

I would clear the codes and see if they return. It is common for the ends of the axles to rust and increase the diameter of the reluctor ring which then hits the ABS sensor. This lights ABS, DSC and ASC lights.

One temporary solution is to install a small shim under the ABS sensor mounting screw. This worked for me for two years, but now the lights are back so it is time for a new axle.

When I bought it, both the ABS and DTC lights were on and the car was undrivable unless you turned off the traction control. Shimming the wheel speed sensor out with a washer worked to solve the DTC problem but the ABS problem remains. I have cleared it multiple times but it always returns. Sometimes it will go off by itself shortly after starting the car but pops back on within a few hundred yards. I'm wondering if shimming out the sensor was enough to resolve the traction control issue but the misshapen reluctor ring(s) are deformed enough that the ABS system can't get a good reading.

I know that the shimming the sensor fix is only a temporary fix and the long-term fix is new axles with an improved reluctor ring design. I plan to do that at some point; however I need to hold off on too much work on this car just yet.

I am retiring in June and my better half agreed to let me get a project car to work on after I retire. Of course, I started looking right away and found this one that does need quite a few things to return it to its glory. For now, I just want to do what is necessary to make it safe to drive and so it will pass inspection if needed (which will not be until December 2022) - I don't need to drive this car as it is #5 in the family fleet.

I put tires on already and will be doing the brakes soon (The PO put new pads on the rear but not new rotors and had purchased front rotors and pads but had not yet put them on so gave them to me. I will use those rotors but have ordered a different set of front pads and a set of rotors for the rear.) The struts/shocks and now, apparently, the axles will need to be done but I think I can hold off until the summer. I've also read of a few instances in which a bad wheel bearing was the culprit for the ABS problem so there may be that as well.

[m_thompson]

Both sensors on my 128i are shimmed. I get ABS/DTC/DSC warnings all the time now, and periodically an airbag light and then the speedometer stops working. I am getting both rear axles replaced next week with GKN brand. Hope that fixes the problem for another 10 years.

[tracer bullet]

Your last question (the hose) was explained but look up "golf tee mod" for more info. I remember that being the common name for it.

[K9Leader]

Originally Posted by m_thompson

Both sensors on my 128i are shimmed. I get ABS/DTC/DSC warnings all the time now, and periodically an airbag light and then the speedometer stops working. I am getting both rear axles replaced next week with GKN brand. Hope that fixes the problem for another 10 years.

Yep, the GKN axles are on my list as well. Please do report back here after yours are done to share whether that resolves the ABS issue for you.

[m_thompson]

Originally Posted by K9Leader

Yep, the GKN axles are on my list as well. Please do report back here after yours are done to share whether that resolves the ABS issue for you.

Two new GKN axles and two new ABS sensors today, and everything is fixed. The ABS, DSC, DTC, and SRS lights are all out.