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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 258 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P1171: Fuel System Lean During Acceleration >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 GMC Sonoma and 2003 Chevrolet S10 Pickup. 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, go to next step.
  2. Operate engine to normal operating temperature. Using scan tool, monitor O2S 1 voltage. Is O2S 1 voltage less than 52 mV? If yes, go to step  4 . If no, go to next step.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Operate 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, see DIAGNOSTIC AIDS  .
  4. Turn ignition off. Disconnect the O2S 1 harness connector. Turn ignition on, with engine off. Does the scan tool indicate that the O2S 1 voltage is 351-551 mV? If yes, go to next step. If no, go to step  6 .
  5. The O2S may be detecting a lean exhaust condition. Inspect O2S connector for water intrusion, exhaust leak between O2S and engine, vacuum leaks, incorrect fuel pressure, or lean fuel injectors. Repair as necessary. Did you find and correct the condition? If yes, go to step  9 . If no, go to step  7 .
  6. Test the O2S high signal circuit for a short to ground or a short to the low signal circuit. Did you find and correct the condition? If yes, go to step  9 . If no, go to step  8 .
  7. Replace O2S 1. After replacing sensor, go to step  9 .
  8. Replace PCM. See appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  9. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start and operate vehicle within Conditions For Running this DTC. See CONDITIONS FOR RUNNING DTC  . Does the DTC run and pass? If yes, go to next step. If no, go to step  2 .
  10. Using scan tool, observe the stored information and capture information. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTCs are displayed, system is okay.
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