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Home >> Chevrolet >> 2001 >> Cavalier LS, 2.2 4 >> Repair and Diagnosis >> External Pages >> Different car >> Section 36 (Engine Controls Self-Diagnostics - 2.4L) >> Diagnostic Tests >> DTC P0134: Ho2S Circuit Insufficient Activity >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
    2. NOTE: If any other DTCs are set, except HO2S DTCs, refer to other DTCs first before proceeding with this test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .
  2. The engine is at operating temperature. Operate engine at greater than 1200 RPM for 2 minutes. With a scan tool, observe the O2s voltage parameter. Does scan tool indicate O2S voltage varying outside the specified values of 400-500 mV? If yes, go to next step. If no, go to step  4 .
  3. Operate vehicle within Failure Records conditions. Does the scan tool indicate this DTC failed this ignition? If yes, go to next step. If no, go to DIAGNOSTIC AIDS  .
  4. Inspect and test for correctly installed O2S or damaged wiring. Did you find and correct the condition? If yes, go to step  13 . If no, go to next step.
  5. Turn ignition off. Disconnect O2S. Jumper the O2S low signal circuit to a good ground. Turn ignition on, with engine off. Measure voltage on O2S high signal circuit on PCM side, using a Digital Multimeter (DMM) that is connected to a good ground. Does the voltage measure within 451-551 mV? If yes, go to next step. If no, go to step  8 .
  6. Jumper the high signal circuit to the low signal circuit on the PCM side. With a scan tool, observe O2s voltage parameter. Does the scan tool indicate O2S voltage at or about 0 mV? If yes, go to step  9 . If no, go to next step.
  7. Test the low signal circuit for an open or high resistance or short to voltage. Did you find and correct the condition? If yes, go to step  13 . If no, go to step  11 .
  8. Test the high signal circuit for an open or high resistance or short to voltage. Did you find and correct the condition? If yes, go to step  13 . If no, go to step  11 .
  9. Inspect for poor connections at the harness connector of the O2S. Did you find and correct the condition? If yes, go to step  13 . If no, go to next step.
    10. NOTE: Determine the cause of contamination before replacing the sensor.
  10. Inspect and test for fuel contamination, engine oil or coolant consumption, or improper use of RTV sealant. Replace the affected O2S. When complete, go to step  13 .
  11. Inspect for poor connections at the PCM harness connectors. Did you find and correct the condition? If yes, go to step  13 . If no, go to next step.
  12. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  13. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC  . Does the DTC run and pass? If yes, go to next step. If no, go to step  2 .
  14. Using scan tool, observe stored information and Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no, system is okay.
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