P0056
P0056Oxygen Sensor Heating Output Stage After TWC, Bank 2 - Open Circuit
Diagnosis conditions
- Battery positive voltage between 10 V and 16 V
- Time elapsed after engine start-up greater than 10 seconds
Possible fault cause
- FE18 fuse faulty (fuse carrier in E-box, radiator tank)
- Loose contact in connector
- Break in wiring in voltage supply of oxygen sensor heating
- Break in wiring in connection to ground of oxygen sensor heating
- Oxygen sensor heating faulty (heating resistance too high)
- DME control module faulty
Affected pins
DME control module connector A, pin 6, and oxygen sensor connector after TWC, bank 2, pin 2
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 ahead of catalytic converter and oxygen sensor after catalytic converter as this will cause implausible fault entries.
Distinguishing feature of both sensors:
Oxygen sensor ahead of catalytic converter (LSU) has a 6-pole connector
Oxygen sensor after catalytic converter (LSF) has a 4-pole 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.
