OBD-II Code P0134 GM – Oxygen sensor circuit open or no activity

P0134 GM Code Description

  • Oxygen sensor circuit open or no activity
  • On V-type engines with two O2 sensors, code P0134 would indicate the left bank sensor

Symptoms:

  • Engine running too rich (black smoke from exhaust) or too lean (lack of power)
  • The engine may run fine with no noticeable dirveability issues

Possible Problems:

  • A failed O2 sensor is the most common cause of a Code P0134
  • A quick test for the O2 sensor circuit from the ECM would be to unplug the O2 sensor and check voltage from the harness side to ground. With the ignition on and the engine off, the reading should be around .5v.
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