GM OBD Trouble Code 65

By Jim Taddei, May 1, 2009

Right bank O2 sensor rich exhaust indicated

The ECM receives a signal from the O2 sensor based on the amount of oxygen in the exhaust. If there is little oxygen in the exhaust, it is in rich condition and the O2 sensor voltage will be high. The ECM uses this information to adjust the amount of fuel delivered to each cylinder. On V-type engines with two O2 sensors, code 65 would indicate the right bank sensor is rich.

Fault Code Description

  • 65 - Right bank O2 sensor rich exhaust indicated


  • Black smoke from exhaust

Common Problems

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