Transfer Box (VG)

Fault Code 2025

Power supply

Diagnostic conditions
- Ignition on
- Internal function test on transfer box control unit

Possible causes of fault
- 'Short circuit to B+' between 'PWM (Pulse Width Modulation) switch' and 'selector switch (in running gear control module)'
- 'Short circuit to ground' between 'PWM (Pulse Width Modulation) switch' and 'selector switch (in running gear control module)'
- 'Open circuit' between 'PWM (Pulse Width Modulation) switch' and 'selector switch (in running gear control module)'

Affected pins
Transfer box control unit connector:
- Pin 7 'PWM (Pulse Width Modulation) switch' to 'pin 4' 'selector switch (in running gear control module)'

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.
- 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.