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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 78 (Engine Controls - Self-Diagnostics - 4.8L, 5.3L & 6.0L) >> Diagnostic Tests >> DTC P0140 & P0160: Ho2S Circuit - Insufficient Activity - Bank 1 & 2, Sensor 2 (W/Isolated Ground) >> Test Description

Test Description

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The number below refers to the step number in the diagnostic procedures.

  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 is varying outside the specified range, the condition is not present.

  3. 6

    If the test lamp illuminates, the low reference circuit between the HO2S and PCM terminal C1-63 is okay and the PCM low reference terminal is okay.

  4. 7

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

  5. 14

    The opposite bank HO2S must be disconnected to isolate a short to ground in the HO2S heater ignition 1 voltage circuit.

  6. 16

    Resistance within the specified range indicates the HO2S heater is okay.

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