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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 123 (Engine Controls - Self-Diagnostics - 4.0L) >> Diagnostic Tests >> DTC P1133 & P1153: Ho2S Bank 1 & 2 Sensor 1 - Insufficient Switching >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. 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  under SELF-DIAGNOSTIC SYSTEM.
  2. Were you sent here from another DTC? If yes, go to step  4. If no, go to next step.
  3. Are any other DTCs set? If yes, diagnose those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  4. Start the engine. Operate the vehicle until the engine reaches the normal operating temperature. View both the engine speed and the affected HO2S display on the scan tool. Operate the engine at 2000 RPM for 2 minutes. Does the HO2S voltage rapidly swing above and below 325-625 mV? If yes, go to next step. If no, go to step  6.
  5. With the engine running at 2000 RPM, observe the scan tool display Loop Status. Does the display indicate Closed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to step  9.
  6. Does the HO2S voltage remain between the specified values longer than the voltage swings outside 325-625 mV? If yes, go to step  9. If no, go to next step.
  7. Test for poor connections at the PCM. If a condition is found, repair as necessary. Did you find and correct the condition? If yes, go to step  10. If no, go to next step.
  8. Test for poor connections at the HO2S. If a condition is found, repair as necessary. Did you find and correct the condition? If yes, go to step  10. If no, go to next step.
  9. Before replacing the oxygen sensor, the cause of contamination must be found and corrected. Test for the following items:
    • High resistance in the HO2S high or low signal circuits.
    • Incorrect or contaminated fuel.
    • An incorrect RTV gasket sealer.
    • An over-rich operation.

    Replace the affected HO2S. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.

  10. Use the scan tool in order to clear the DTCs. 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.
  11. With a scan tool, observe the stored information, Capture Info. 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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