P0420

P042000

Diagnostic information - DME control unit

Exhaust gas temperature sensor

DANGER
High voltage.
Death or severe injuries due to high voltage or high current.

- De-energise the vehicle in accordance with the guidelines.
- Work must not be performed on parts carrying a high voltage.

The control unit must be active in order to test internal function sequences and diagnosable inputs/outputs.
In the event of a fault, check whether the fault is permanently >present<. To perform the check, erase the fault memory, meet the diagnostic conditions and read out the fault memory again.

NOTE:
- Sensor voltage not OK

Diagnostic conditions
- Ignition on

Possible fault causes
- Short circuit to ground
- Signal implausible
- Electrical fault