marcmayer

ABS/ESP failure message went on when backing out of a parking spot tonight. I turned off the car a minute later and turned back on and the errors cleared. Pulling into my driveway 10 minutes later they are back. Scanned and don't see any codes in brake module. Scanner says PTS and Backup camera modules not detected (backup camera still works; PTS disabled on dash). I did have the following related codes though:

TCM code D409 - No CAN message received from control unit N47-5 (ESP and BAS Control Module)
ISM code 1960 - No CAN message was received from control unit N47-5 (ESP control unit)
ECM code 1425 - Wheel speed signal is implausible.

I've got good fuses and grounds for PTS and adaptive ABR.

Initially I thought I had a bad brake module, but with PTS and backup models down at same time, perhaps a CAN bus issue?
I'm open to ideas.

Plutoe

You have an isue with the wheel speed sensor(s)

marcmayer

Thanks - Shouldn't that log a code on the brake module?

Plutoe

There are many modules that require the wheel speed signal to function------that's why the faults---I have no idea what you are calling a brake module,but the TCM is telling you its not receiving a signal from the ESP BAS--thats a fault

marcmayer

Thanks again Plutoe.

"I have no idea what you are calling a brake module"

My scan tool (Launch X431) lists the brake module as the ABR ( Adaptive Brake System ) module. This is shown in WIS as the N47-5 module attached directly the ABS hydraulic/motor unit and is apparently sometimes referred to as the ESP control unit or the ESP and BAS Control Module. This module is directly wired to the wheel speed sensors.

In retrospect you are absolutely correct - the "ECM code 1425 - Wheel speed signal is implausible" should have pointed me directly to the sensors. The thing that threw me is that the brake module (ABR) shows no codes. Since this is the module directly wired to the speed sensors, I figured that if it had enough info to report to the ECM that wheel speed signal is implausible that it would have recorded the fault, and ideally even have the corner info. FWIW, I did use scan tool to see/record the wheel sensor data at all 4 corners during a test drive, and all were reporting accurately with no apparent glitching. Despite that, I cleaned the sensors and magnet rings. At least for the moment, this resolved the issue. If it doesn't stay fixed, I'll replace the sensors next. Wish I knew which corner was the one to target.

UPDATE: Fault recurred: 4 sensors ordered.

Jason Zimbran

marcmayer

Thanks - how did you identify which sensor was the culprit?

Jason Zimbran

I work at a Honda store where a Tech plugged it in and came back with the code for the speed sensor on the left side, replaced it and now it’s golden. I was worried because all the lights flashed, brake detection, blind spot, abs, esc, lane departure. But that solved the problem. $70 part. Hope it’s a minor thing

marcmayer

I ended up replacing all 4 sensors which resolved the issue.

Super easy to swap them in. 1 E-10 bolt at wheel hub . Disconnect connector from car (its paired with another sensor with the connectors snapping together so you pull 2 at once) by pushing the bare metal wire on the car side of the connector towards the connector with a pick or screwdriver while pulling the connector out. Re-route new sensor wire along same path - snap ends together and reinsert.

In the rear - you also need to remove 3 plastic 10mm nuts to gain access under the inner wheel arch cover (connectors are protected from road debris / snow / rain under the cover).

I used ATE brand sensors. They are the supplier to MB. Inspecting the ATE sensors you can see where each has had the MB part number / logo scraped off the wire surface. Absolute OEM fit/function at fraction of dealer cost - but not exactly cheap (US$260 for all 4). ATE part numbers for my '08 S550 4matic were:

Rear: 360333
Front: 360385