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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 103 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P1133: Ho2S Insufficient Switching (Bank 1; Sensor 1 - DOHC) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, 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 for HO2S DTCs, refer to the other DTCs first before proceeding with this test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  2. Operate engine at normal operating temperature. Operate engine at greater than 1200 RPM for 2 minutes. With a scan tool, observe the HO2S 1 voltage parameter. Does the scan tool indicate that the HO2S 1 voltage is varying at greater than and less than the specified values of 350-550 millivolts? If yes, go to next step. If no, go to step  4.
  3. Start engine. Idle engine at normal operating temperature. Operate vehicle within code enable criteria. If scan tool indicates DTC failed this ignition cycle, go to next step. If scan tool does not indicate DTC failed this ignition cycle, problem is intermittent. Refer to INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition off. Disconnect HO2S 1. Turn ignition on, with engine off. Using a Digital Multimeter (DMM), measure the voltage of the HO2S 1 high signal circuit on the PCM side to a good ground. Does the voltage measure within 350-550 millivolts? If yes, go to next step. If no, go to step  9.
  5. Turn ignition off. Connect a 3-amp fused jumper wire between the HO2S 1 high signal circuit and HO2S 1 low signal circuit. Turn ignition on. Use a scan tool in order to monitor the HO2S 1 voltage for the sensor that applies to this DTC. Does scan tool indicate that HO2S 1 voltage is less than 20 millivolts? If yes, go to next step. If no, go to step  10.
  6. Turn ignition off. Remove the 3-amp fused jumper wire. Connect a test light between ignition 1 voltage circuit and a good ground. DO NOT use the HO2S 1 heater low control. Turn ignition on, with engine off. Does test light illuminate? If yes, go to next step. If no, go to step  11.
  7. Connect a test light between ignition 1 voltage circuit and HO2S 1 heater low control circuit. Turn ignition on, with engine off. With a scan tool, command the HO2S 1 heater ON and OFF. Does test light turn ON and OFF with each command? If yes, go to step  14. If no, go to next step.
  8. Does test light remain illuminated with each command? If yes, go to step  12. If no, go to step  13.
  9. Test HO2S 1 high signal circuit for open, high resistance, short to ground or short to voltage. Did you find and correct the condition? If yes, go to step  19. If no, go to step  16.
  10. Test HO2S 1 low signal circuit for an open, high resistance or short to voltage. Did you find and correct the condition? If yes, go to step  19. If no, go to step  16.
  11. Test ignition 1 voltage circuit for an open, high resistance or short to ground. Replace ERLS fuse if necessary. Did you find and correct the condition? If yes, go to step  19. If no, go to step  15.
  12. Test HO2S 1 low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step  19. If no, go to step  16.
  13. Test HO2S 1 low control circuit for an open, high resistance or short to voltage. Did you find and correct the condition? If yes, go to step  19. If no, go to step  16.
    14. NOTE: Before replacing the HO2S 1, check and remove any source of contamination.
  14. Inspect for improper use of incorrect silicone RTV sealant, fuel contamination, exhaust leak, improperly installed HO2S or damaged wiring. Did you find and correct the condition? If yes, go to step  19. If no, go to next step.
  15. Inspect for poor connections at the harness connector of the HO2S 1. Did you find and correct the condition? If yes, go to step  19. If no, go to step  17.
  16. Inspect for poor connections at the PCM harness connector. Did you find and correct the condition? If yes, go to step  19. If no, go to step  18.
  17. Replace HO2S 1. When complete, go to step  19.
  18. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to next step.
  19. Use scan tool in order to clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  20. With a scan tool, observe the stored information, Capture Info. Does 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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