4x4 light

[dubwud]

Hi XDrivers,

Apologies if this is a repeat post, I’ve done a few searches on here and using Google, but I’ve not managed to resolve my specific issue…

Recently the 4x4 light illuminated on my dashboard, fixed and in yellow. No other lights are illuminated and the car drives completely fine.

I had the car diagnosed and the fault code read “DSC no communication”. I’ve spoken to a couple of mechanics on this and can’t seem to identify the actual error. One mechanic said it was because I recently had a rear tyre change (only one side) and the DSC/ABS/TPMS uses the rolling radius of the tyre to establish the wheel position and height, since this couldn’t be established, some internal communication is not being made, and the 4x4 system shows a fault. I had the fault cleared, but it came back again instantly. Perhaps coincidently, when the tyre was first changed, the TPMS light did come on followed shortly by the 4x4 light. After resetting the TPMS I assume the 4x4 would also reset, but it did not.

Another couple of things that may be important to note, is that a few months ago, I started my car and the message “SELFLEVEL SUSP.INACT” was displayed. But this soon cleared and has not been seen since. Secondly, I recently had an issue with my starter motor, which meant I was attempting to start the car over and over again, and occasionally, as a result, the ECU would start displaying various non-existent faults due to low battery voltage. The sporadic faults would always clear once the car started and the battery voltage was restored to 11V+. I don’t know whether the low voltage could’ve caused an error with the 4x4 which has since latched.

I don’t really know where else to turn, as I said above, the car drives faultlessly, any help or suggestions for things to check would be greatly appreciated.

Jack.

[dubwud]

Apologies - probably should mention the car is a 2005 E53 3.0d sport.

[henrym3]

I assume you have tried turning the steering from lock to lock while driving slowly forward.

[dubwud]

I assume you have tried turning the steering from lock to lock while driving slowly forward.

Thanks for the response. I have. I’ve tried multiple times both whilst stationary and whilst driving forwards. The light remains on.

[marti]

Have you changed your battery or got it up to 12V+ , 11V is way to low...should be 14V+ when running...

[dubwud]

Have you changed your battery or got it up to 12V+ , 11V is way to low...should be 14V+ when running...

The 4x4 light appeared around the same time the starter motor began to fail, which required me to attempt to start the car several times before it started - this lead to a couple of battery failures due to the high current driving the starter multiple times. But, once I had the starter replaced, I checked the battery and it was back up at the expected ~12.5V when the engine was off, and ~14V when the engine was running. I've not checked the voltage recently, but will do so tonight and confirm.

Thanks again for your help.

[henrym3]

Next suggestion would be to disconnect the battery, both terminals and then touch the terminals together for 30 seconds, this will get rid of any stored faults. Note when you start up and before you drive if the 4x4 light comes on or not. If not then drive and see if it returns.