A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
Possible causes
- The 4WD mode sensor or switch
- The transfer case or AWD control unit
- The CAN bus between the units
What you can do yourself
- ESP and traction control, and sometimes ABS, may not work. The brakes still work, but without electronic help — on slippery roads brake smoothly and don’t accelerate hard.
- Four-wheel drive or low range may not engage. Be careful on slippery roads and off-road.
Stop and don’t drive on if:
- The red brake light is on, or the brake pedal feels soft or sinks
- The steering became very heavy, or the car pulls to one side when braking
If the scan tool shows the code with a suffix after a dash (for example, C0031-1D), that’s the fault detail: 01 — general electrical failure, 1D — circuit current out of range, 29 — invalid signal, 2F — erratic signal, 62 — signal doesn’t match the others.
The explanation comes from the error code reference in the AvtoElektrik PRO app.