P0155
P0155Oxygen sensor heating in front of catalytic converter, bank 2 - signal implausible/below limit value/above limit value/open circuit
Diagnostic conditions
- Battery positive voltage between 10 V and 16 V
- Time after the engine is started longer than 10 seconds
- Exhaust temperature greater than 600 °C
- Oxygen sensor heating control active
- No oxygen sensor output stage fault in memory
Possible cause of fault
- Oxygen sensor faulty
- Contact resistance between DME control module and oxygen sensor heating ahead of catalytic converter, bank 2
- Contact resistance between fuse FE 18 in fuse carrier for E-box, radiator tank, and oxygen sensor heating ahead of catalytic converter, bank 2
- High-resistance shunt circuit to signal wire
- Only fault type "open circuit" DME control module faulty
Affected terminals
DME control module connector A, pin 4, and oxygen sensor connector, pin 4
Diagnosis/troubleshooting
NOTE: Do not use contact spray on the oxygen sensor plug connections, as this may cause irreparable damage to the wiring (blocking the reference air channels).
NOTE: Do not confuse oxygen sensor in front 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.
NOTE: 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.
Oxygen sensor heating in front of catalytic converter, bank 2 - signal implausible
Oxygen sensor heating in front of catalytic converter, bank 2 - below limit value
Oxygen sensor heating in front of catalytic converter, bank 2 - above limit value
Oxygen sensor heating in front of catalytic converter, bank 2 - open circuit
