Tom M

I've got 100K miles at present and decided to adjust the EPB on Saturday as it seemed like they weren't grabbing as snugly as they should. I followed the procedure listed on AllDataDIY and then used the X431 iCarScan w/EZ Diag to cycle things and verify the values. Everything seemed to work but it failed on the calibration update. Didn't think much of it as the EPB seemed to be working fine so I turned everything off. However, when I drove to work today I noticed I had an EPB fault on the display.

Long story short, I now have a fault warning the EPB is in service mode. I can clear the fault with the X431 but as soon as I disconnect it returns. If I leave the SW running the fault seems to stay off. I also read out the faults with the Durametric and get the same error codes. Clearing the fault behaves the same so I'm guessing the EPB control unit thinks it's in service mode still.

Hopefully I'm just missing something on the EZ Diag on how to exit service mode but it's certainly not intuitive. I will investigate more tonight when I get home but any ideas/suggestions are welcome.

deilenberger

What's the EPB? Electronic parking brake? You might be right - it may have not exited service mode since the calibration failed. You might want to run the full system fault-code scan. I notice if that's done - it apparently puts the EPB into service mode (displays on the multi-function-display screen) and then takes it out, Perhaps if you first clear the code - then run the full scan - that might do it.

Tom M

I actually tackled this again last night and was finally able to get the calibration to complete.

I tried using the Durametric on it last night as well as that places the EPB into service mode and back out but there was no change in the fault code. Most likely this was due to not having completed the calibration.

The real issue seems to be that the communication fails for some unknown reason when moving to the next step and then it's necessary to turn off the car and restart at the failed step. This means you also need to back up in the app so it "forgets" that it had the error as not doing so doesn't let it recover. After finally getting the "Grinding In" process to complete then the Calibration step ran to completion - no more fault code.

Now I just need to track down the root cause of the passenger rear door lock not operating correctly.

edpsf415

Out of curiosity, how were you able to get to the "grinding in" process? I have an icarscan tool but I only see the read basic setting (determines the air gap) and calibrate. However calibrate fails, presumably because the grinding in process was not completed. I'm guessing I need to track down a PIWIS for this but it sounds like you were able to accomplish this without one?

garrett376

Did you replace the locking unit? I just did mine a couple weeks ago due to it failing.

Tom M

I honestly don't recall right now. I think I just went through the steps and at some point it asked about if it needed to be done (i.e. did the parking brake pads get replaced or some such) and I said it wasn't needed.

I did replace the locking unit. It's not too hard but fairly complicated. I picked up a used one from a Panamera that has the same p/n stamped on the mechanism but different cable lengths so I simply swapped the cables over. Everything works fine now.