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Home >> Buick >> 2001 >> Century Limited >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 3.1L & 3.4L >> Diagnostic Tests >> DTC P0030: Ho2S 1 Heater Circuit >> Diagnostic Procedure (Alero, Grand Am, Impala, Malibu & Monte Carlo)

Diagnostic Procedure (Alero, Grand Am, Impala, Malibu & Monte Carlo)

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. Start engine and warm to normal operating temperature. Allow engine idle to stabilize for at least one minute. Using scan tool, monitor O2 HEATER CURRENT. If scan tool displays .25-.85 amp, see INTERMITTENT TROUBLE CODE DETERMINATION  under SELF-DIAGNOSTIC SYSTEM. If scan tool does not display .25-.85 amp, go to next step.
  3. Check ERLS fuse (10-amp) located in underhood fuse block. If fuse is open, go to step  11. If fuse is okay, go to next step.
  4. Turn engine off. Turn ignition on. Disconnect HO2S 1 harness connector. See Fig 1. Connect a test light between ground and ignition 1 voltage circuit (Brown wire) at HO2S 1 harness connector terminal "D". If test light illuminates, go to next step. If test light does not illuminate, go to step  7.
  5. Connect test light between ignition 1 voltage circuit (Brown wire) at HO2S 1 harness connector terminal "D" and HO2S 1 heater low control circuit (Black/White wire) at HO2S 1 harness connector terminal "C". Start engine. If test light illuminates, go to step  9. If test light does not illuminate, go to next step.
  6. Turn ignition off. Connect test light between ground and HO2S 1 heater low control circuit (Black/White wire) at HO2S 1 harness connector terminal "C". Start engine. If test light illuminates, go to step  8. If test light does not illuminate, go to step  12.
  7. Repair open in ignition 1 voltage circuit (Brown wire) between HO2S 1 and underhood fuse block. See WIRING DIAGRAMS article. After repairs, go to step  14.
  8. Repair short to voltage in HO2S 1 heater low control circuit (Black/White wire) between HO2S 1 harness connector terminal "C" and PCM harness connector C2 terminal No. 37. See PCM LOCATION . See Figure or Figure . After repairs, go to step  14.
  9. Check for poor connections or poor terminal tension at HO2S 1 harness connector. If a poor connection is found, replace terminals. After repairs, go to step  14. If no poor connections are found, go to next step.
  10. Replace HO2S 1. After repairs, go to step  14.
  11. Repair short to ground in ignition 1 voltage circuit (Brown wire) between HO2S 1 and underhood fuse block. Replace fuse. See WIRING DIAGRAMS article. After repairs, go to step  14.
  12. Check for poor connections or poor terminal tension at PCM harness connector. If a problem is found, repair as necessary. After repairs, go to step  14. If a problem is not found, go to next step.
  13. Replace PCM. Program replacement PCM using required equipment. See PROGRAMMING . After repairs, go to next step.
  14. Start engine and warm to normal operating temperature. Allow engine idle to stabilize for at least one minute. Using scan tool, monitor O2 HEATER CURRENT. If scan tool displays .25-.85 amp, go to next step. If scan tool does not display .25-.85 amp, go to step  2.
  15. Using scan tool, observe all stored information. If scan tool displays any DTCs that have not been diagnosed, diagnose those DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs, system is okay.
Fig 1: Locating Engine Control Components On Right Side Of Engine (Alero, Grand Am, Impala, Malibu & Monte Carlo)
G00051971Courtesy of GENERAL MOTORS CORP.
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