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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 P0135, P0141, P0155 & P0161: Ho2S Heater Circuit - Bank 1 & 2, Sensors 1 & 2 (4.8L & 5.3L W/Case Ground) >> Diagnostic Aids

Diagnostic Aids

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NOTE: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
  1. Use the Freeze Frame/Failure Records in order to help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Freeze Frame/Failure Records can help to determine how many miles have occurred since the DTC set. The Fail Counter and the Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass or a fail. In order to isolate when the DTC failed, operate the vehicle within the same Freeze Frame conditions such as RPM, load, vehicle speed, temperature, etc. that you observed.
  2. The heater diagnostic will only run on a cold start and run once per ignition cycle.
  3. An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provide the supply of oxygen. Inspect the HO2S wires and inspect the connections for breaks or for contamination.
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