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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 43 (Engine Control System Self-Diagnostics - 3.8L) >> Diagnostic Tests >> DTC P0135: Ho2S Heater Circuit - Bank 1, Sensor 1 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. 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, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
    2. NOTE: If engine has just been operating, allow engine to cool for about one half hour before proceeding.
  2. Turn ON the ignition. With a scan tool, observe the HO2S voltage parameter. Does HO2S voltage go from bias voltage to more than 600 mV or less than 300 mV? If yes, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  3. Inspect the fuse for the HO2S 1 voltage circuit. Is the fuse open? If yes, go to step  13. If no go to next step.
    4. NOTE: Use a known-good ground. DO NOT use the HO2S heater ground or low signal circuit.
  4. Disconnect the HO2S. Probe the ignition 1 voltage circuit, on the PCM harness side, with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step  7.
  5. Connect the test lamp between the HO2S ignition 1 voltage circuit and the HO2S heater ground. Does test lamp illuminate? If yes, go to next step. If no, go to step  8.
  6. Allow the HO2S to cool for at least 10 minutes. Measure the resistance between the HO2S ignition 1 voltage and HO2S heater ground at the pigtail using a DMM. Does the resistance measure 5-10 ohms? If yes, go to step  9. If no, go to step  12.
  7. Repair the open HO2S ignition 1 voltage circuit. After repairs, go to step  14.
  8. Repair the open HO2S heater ground circuit. After repairs, go to step  14.
  9. Inspect for a poor connection at the HO2S. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  10. Test the HO2S high signal and HO2S low signal circuits for an open. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  11. Inspect the HO2S high signal or HO2S low signal circuits for a poor connection at the PCM and HO2S. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  12. Replace the HO2S. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  14.
  13. Repair the short to ground in HO2S ignition 1 voltage circuit and replace the fuse. After repairs, go to next step.
  14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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