Oxygen Sensor Downstream of Cat. Conv.

P227300

Diagnostic information - DME control unit

Oxygen sensor downstream of cat. conv.

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:
- Check exhaust system for leaks

The leak tightness of the exhaust system is of great importance for systems with oxygen sensors. Exhaust gas pulsing results in oxygen being sucked in through leaks in the exhaust system.

Diagnostic conditions
- Idling

Possible fault causes
- Short circuit to B+
- Short circuit to ground
- Limit exceeded
- Below limit
- Signal too slow
- Pump current, open circuit
- Reference voltage, open circuit
- Ground line, open circuit
- Leak