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Home >> Chevrolet >> 2001 >> Tracker 2D Utility, 4WD, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics >> Diagnostic Tests >> DTC P0172: Rich Fuel Trim System >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
  2. Operate vehicle while loop status indicates CLOSED LOOP on scan tool. Observe short term fuel trim parameter on scan tool. If scan tool displays greater than -11 percent, go to next step. If scan tool displays less than -11 percent, go to step  4 .
  3. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within FREEZE FRAME conditions. Observe total fuel trim parameter on scan tool. If scan tool displays -30 percent or greater, go to DIAGNOSTIC AIDS  . If scan tool does not display -30 percent or greater, go to next step.
  4. Visually and physically check air intake system for restrictions. Repair as necessary. After repairs, go to step  10 . If no problems exist, go to next step.
  5. Turn ignition off. Install fuel pressure gauge. Start engine. Warm engine to normal operating temperature. Observe fuel pressure at an idle. If fuel pressure is 36-43 psi (2.5-3.0 kg/cm2 ), go to next step. If fuel pressure is not 36-43 psi (2.5-3.0 kg/cm2 ), diagnose fuel system as necessary. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
  6. Check EVAP system for possible over purging of fuel vapors. Repair as necessary. After repairs, go to step  10 . If no problems exist, go to next step.
    7. NOTE: Before replacing HO2S No. 1, inspect sensor for contamination. If contamination is present, determine cause and repair before installing new HO2S No. 1.
  7. Turn ignition off. Remove HO2S No. 1. Check HO2S No. 1 for damage or contamination. Replace as necessary. After repairs, go to step  10 . If HO2S No. 1 is not damaged or contaminated, go to next step.
  8. Check fuel injectors for regular and even fuel discharge, fuel leaking from ball valve of injector, and fuel dispersed in a conical spray pattern. Ensure injector coil resistance is within specification. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTIC PROCEDURES article. If problem(s) exists, go to next step. If no problems exist, go to DIAGNOSTIC AIDS  .
  9. Replace faulty fuel injectors. After repairs, go to next step.
  10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the conditions for running the DTC. See CODE ENABLE CRITERIA  . If DTC runs and passes, go to next step. If DTC resets, go to step  2 .
  11. Turn ignition on, with engine off. Using scan tool, observe the stored information and Capture Info. 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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