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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 335 (Engine Controls - Self-Diagnostics - 3.0L) >> Diagnostic Tests >> DTC P0134 Or P0154: Ho2S Circuit - Insufficient Activity >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS .
  2. Is DTC P0135 or P0155 also set? If yes, go to DTC P0135, P0141, P0155 0R P0161: HO2S HEATER CIRCUIT . If no, go to next step.
  3. Allow the engine to idle at operating temperature. Observe the affected HO2S 1 voltage parameter using a scan tool. Clear the DTCs and record the Freeze Frame/Failure Records. Operate the engine at 2000 RPM for at least one minute, then allow to idle. Vary the engine speed from idle to 3000 RPM several times within 5 seconds. Does the affected HO2S voltage fluctuate greater than and less than 400-597 mV? If yes, go to next step. If no, go to step  5.
  4. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition off and wait until scan tool communication is lost. Start engine. Operate vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? go to step 5 If no, problem is intermittent. Refer to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L & 3.0L VUE article.
  5. Turn ignition off. Disconnect the affected HO2S connector. Connect a 3-amp fused jumper wire between the affected HO2S high signal circuit of the engine harness connector and a good ground. Turn ignition on, with engine off. Observe the affected HO2S voltage parameter with a scan tool. Is the HO2S high signal voltage less than 25 mV? If yes, go to next step. If no, go to step  7.
  6. Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire between the affected HO2S high signal circuit and the HO2S low signal circuit on the engine harness side. Observe the affected HO2S voltage with a scan tool. Is the affected HO2S voltage less than 25 mV? If yes, go to step  10. If no, go to step  8.
  7. Test the HO2S high signal circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  15. If no, go to step  12.
    8. NOTE: The ECM may have been damaged if the circuit was shorted to a voltage source.
  8. Test the HO2S low signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  9. Test the affected HO2S low signal circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  15. If no, go to step  12.
  10. Inspect for the following that may affect the HO2S operation: HO2S contamination, chafed, burnt, cut, pinched, or otherwise damaged HO2S wiring, EVAP system malfunction, or incorrect fuel pressure that can affect HO2S operation. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  11. Test for an intermittent and for a poor connection at the affected HO2S connector. Did you find and correct the condition? If yes, go to step  15. If no, go to step  13.
  12. Test for an intermittent and for a poor connection at the ECM harness connectors. Did you find and correct the condition? If yes, go to step  15. If no, go to step  14.
  13. Replace affected HO2S. After replacing sensor, go to step  15.
  14. Replace ECM. Perform ECM relearn procedures. See ENGINE CONTROL MODULE  under PROGRAMMING. After replacing ECM, go to next step.
  15. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  16. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, diagnose affected DTC(s). See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
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