Tire Pressure Monitoring System

Fault Code 0668

Vehicle voltage, terminal 30

Diagnostic conditions

- Control module for tire pressure monitoring system, internal function test

Possible cause of fault

- Lower limit value not reached (battery voltage too low)
- Short circuit to ground or open circuit in wiring
- Fault in control module for vehicle electrical system (read out fault memory of vehicle electrical system control module)
- Fuse faulty (fuse carrier F24 at left of dashboard)
- Ground connection not OK
- Control module faulty

Affected pins

Plug on control module for tire pressure monitoring system:
- Pin 2 'terminal 30'
- Pin 1 'terminal 31'
- Fuse F24 (5A) in fuse carrier at left of dashboard

Diagnosis/troubleshooting

NOTE:
- Visual inspection: In the next troubleshooting section, please check first that the affected pins on the plug connection for the tire pressure monitoring system control module are neither damaged nor corroded. The wiring and plugs of the affected components must also be checked for external damage and correct contacts. Repair damaged or corroded pins if possible, otherwise replace affected pins. Repair or replace damaged wires.
- Sporadic faults: In the event of faults that occur sporadically, the wiring positions that are linked to moving parts on and in the vehicle must be checked for each system. Various statuses that can cause faults must be simulated with the help of the wiring diagram.
- Battery voltage: A battery voltage of between 11.4 and 14.5 V is required for the following troubleshooting procedure. This must be checked and provided, if necessary. On the vehicle electrical system, the voltage to the fuse (input side) must be guaranteed.

Part 1:

Part 2: