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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 103 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0140: Ho2S 2 Circuit - Insufficient Activity (SOHC) >> Test Description

Test Description

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

The number below refer to the step number on the diagnostic procedure.

  1. 2

    After the ignition is turned ON, the HO2S heater heats up causing the HO2S signal voltage to either increase or decrease. This indicates that the HO2S heater is okay.

  2. 3

    If the HO2S voltage changes more than the specified value, the condition is not present.

  3. 5

    If the voltage is below the specified value, the high signal circuit, the low signal circuit, and the PCM are okay.

  4. 6

    If the voltage is at greater than the specified value, the low signal circuit is okay.

  5. 14

    Resistance below the specified value indicates the HO2S heater is shorted.

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