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Home › Saturn › 2003 › L200 Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P1171: Fuel System Lean During Acceleration › Diagnostic Procedures

Diagnostic Procedures

  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. Operate the engine at normal operating temperature. Operate the engine at more than 1200 RPM for 2 minutes. Observe the HO2S 1 voltage parameter with a scan tool. Does the scan tool indicate that the HO2S 1 voltage is less than 300 mV? If yes, go to step  4. If no, go to next step.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition off for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to DIAGNOSTIC AIDS .
  4. Turn ignition off. Disconnect the HO2S sensor. Turn ignition on, with engine off. Measure the voltage of the HO2S 1 high signal circuit on the PCM side with the DVOM. Does the voltage measure within 350-550 mV? If yes, go to step  6. If no, go to next step.
  5. Test the HO2S 1 high signal circuit for a short to ground or a short to the HO2S 1 low signal circuit. Did you find and correct the condition? If yes, go to step  11. If no, go to step  8.
  6. The HO2S 1 is detecting a lean condition or may be contaminated. Inspect HO2S connector for water intrusion, silicone-contaminated HO2S, exhaust leak between HO2S 1 and engine, vacuum leaks, incorrect fuel pressure, or lean fuel injectors. Repair any of the conditions as necessary. Did you find and correct the condition? If yes, go to step  11. If no, go to next step.
  7. Inspect for poor connections at the harness connector of the HO2S 1 sensor. Did you find and correct the condition? If yes, go to step  11. If no, go to step  9.
  8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step  11. If no, go to step  10.
    9. NOTE: Before replacing the HO2S determine and remove any source of contamination.
  9. Replace the HO2S 1. After replacement, go to step  11.
  10. Replace PCM. See POWERTRAIN CONTROL MODULE in REMOVAL & INSTALLATION - SATURN "L" SERIES article. Perform PCM relearn procedure. See PCM REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to next step.
  11. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  12. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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