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Home >> Buick >> 2002 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.1L Engine >> Diagnostic Tests >> DTC P0140: Ho2S Circuit Insufficient Activity (Bank 1; Sensor 2) >> Test Description

Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

  1. 2

    The HO2S 2 voltage may default to the bias voltage. The DTC should be cleared and the Freeze Frame/Failure Records data recorded before proceeding. A normally functioning HO2S 2 voltage signal will fluctuate at greater than and less than the bias voltage amount. The action in the test step should result in a visible reaction from the HO2S 2 output.
  2. 4

    A voltage reading other than the specified amount in this step indicates an open circuit condition in one of the signal circuits or the PCM.
  3. 5

    This step inspects for an open circuit condition in the signal circuits, independent of the PCM.
  4. 7

    The conditions listed in the table may contribute to the failure of the HO2S. The conditions listed apply only to this type of failure.