P2250

P225O

Oxygen Sensor Ahead Of Catalytic Converter, Bank 2 - Nernst Voltage Line - Above Limit

Diagnostic conditions
- Battery voltage between 10 V and 16 V
- Time after the engine is started longer than 10 seconds

Possible cause of fault
- Check Nernst voltage line for short circuit to B+
- Oxygen sensor faulty (internal short circuit or intercore short circuit)
- DME control module faulty

Affected terminals
DME control module connector A, pin 13, and oxygen sensor connector ahead of TWC, bank 2, pin 1

Diagnosis/troubleshooting

NOTE:
- Do not use contact spray on the oxygen sensor plug connections as this may cause irreparable damage to the wiring (contamination of the oxygen sensor via the reference air channel).
- Do not confuse oxygen sensor ahead of catalytic converter and oxygen sensor behind catalytic converter as this will cause implausible fault entries.

Distinguishing feature of both sensors:







Oxygen sensor in front of catalytic converter (LSU) has a six-pin connector







Oxygen sensor behind catalytic converter (LSF) has a four-pin connector

NOTE:
- If connector A is disconnected from the DME control module and the ignition is or was switched on, the 'DME Control Module TIMEOUT' fault is recorded in many control modules.
- If control module connector A was disconnected from the DME in the course of troubleshooting or if the voltage supply was interrupted elsewhere (battery, fuse), the throttle adjusting unit must be adapted.