Fault code 2025: Diagnosis/troubleshooting

NOTE: Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' on the transfer box control unit plug connection and the 'pins' on the plug connections on the 'selector switch (in running gear control module)' are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wiring.

NOTE: Control unit replacement: before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked and found to be OK. After test-driving the vehicle, read out the fault memory again using the 9718 PIWIS tester. Additional causes of faults that could damage the 'transfer box control unit' should be detected and remedied.

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Work instruction		Display OK	If not OK
1	Carry out the following checks on the wiring between 'pin 7' 'transfer box control unit' and 'pin 4' 'selector switch (in running gear control module)': Short circuit to B+ Short circuit to ground Open circuit	Go to Step 2	Repair or replace connector/wiring. → End
2	Replace selector switch (running gear control module)	→ End