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Home >> Pontiac >> 2001 >> Aztek Base, FWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P0135: Heated Oxygen Sensor No. 1 Heater Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
  2. Start engine and allow idle to stabilize for about one minute. Engine should be at normal operating temperature. Using scan tool, monitor HO2S heater current. If current is 0.25-0.85 amp, problem is intermittent. If current is not 0.25-0.85 amp, go to next step.
  3. Turn ignition off. Check fuse (15-amp) to HO2S 1 ignition 1 voltage circuit. Fuse is located in underhood fuse/relay block. If fuse is open, go to step  13. If fuse is okay, go to next step.
  4. Turn ignition on, with engine off. Disconnect HO2S 1 harness connector. Connect a test light to a known-good ground and probe HO2S 1 harness connector terminal "D" (Pink wire). See Figure. If test light illuminates, go to next step. If test light does not illuminate, go to step  8.
  5. Connect test light between HO2S 1 harness connector terminals "A" (Tan wire) and "D" (Pink wire). Start engine. If test light illuminates, go to next step. If test light does not illuminate, go to step  7.
  6. Turn engine off. Turn ignition on, with engine off. If test light illuminates, go to step  10. If test light does not illuminate, go to step  11.
  7. Turn ignition off. Disconnect PCM harness connector. Using DVOM, check resistance in Black/White wire between PCM harness connector C2 terminal No. 37 and HO2S harness connector terminal "C". If resistance is 0-5 ohms, go to step  14. If resistance is not 0-5 ohms, go to step  9.
  8. Turn ignition off. Repair open in Pink wire between HO2S 1 harness connector terminal "D" and underhood fuse/relay block. After repairs, go to step  16.
  9. Repair open or high resistance Black/White wire between HO2S 1 harness connector terminal "C" and PCM harness connector C2 terminal No. 37. After repairs, go to step  16.
  10. Check for short to ground in Black/White wire between HO2S 1 harness connector terminal "C" and PCM harness connector C2 terminal No. 37. After repairs, go to step  16. If circuit is okay, go to step  14.
  11. Turn ignition off. Check for poor connections or poor terminal tension at HO2S 1 harness connector. Repair or replace as necessary. After repairs, go to step  16. If connections or terminals are okay, go to next step.
  12. Replace HO2S 1. After replacing sensor, go to step  16.
  13. Locate and repair short to ground in Pink wire between HO2S 1 harness connector terminal "D" and underhood fuse block. Replace fuse. After repairs, go to step  16.
  14. Check for poor connections or terminal tension at PCM harness connector. Repair as necessary. After repairs, go to step  16. If connections or terminal tension is okay, go to next step.
  15. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  16. Start engine and allow idle to stabilize for about one minute. Engine should be at normal operating temperature. Using scan tool, monitor HO2S heater current. If heater current is 0.25-0.85 amp, go to next step. If heater current is not 0.25-0.85 amp, go to step  2.
  17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Review CAPTURED INFO using scan tool. If any undiagnosed DTCs are displayed, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
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