P0139

DTC P0139
Lambda sensor aging downstream bank 1 Drive cycle C:Signal out of range - above maximum.

DTC P0139
Lambda sensor aging downstream bank 1 Drive cycle C:Signal out of range - below minimum.

Possible cause:
^ Deteriorated oxygen sensor.

Deteriorated Oxygen Sensor.

POSSIBLE FAULTS

^ The Motronic ECM has internally diagnosed that the switching characteristics of this oxygen sensor have degraded to a point where on board diagnostics will be affected.

^ This fault is normally caused by the aging of the sensor in normal operation, however, this effect can be accelerated if the sensor has been contaminated with oil or other surface contamination.