LEMON Manuals: Even more car manuals for everyone
Home >> Isuzu >> 2000 >> Rodeo LSE, 2.2 D >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Trouble Code Identification >> DTC P0171: Fuel Trim System Lean >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic II (OBD-II) system check. See SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
  2. If any DTC other than P0171 is set, diagnose affected DTC before proceeding. If no other DTC is set, go to next step.
  3. Operate vehicle in closed loop. Using scan tool, read BANK 1 LT FUEL TRIM values. If LT FUEL TRIM value is greater than 20 percent, go to step  5. If value is not as specified, go to next step.
  4. Using scan tool, read and record FAILURE RECORDS data. Clear DTCs and operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read specified DTC while operating vehicle. Continue operating vehicle until DTC P0171 test runs. If scan tool displays DTC P0171 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0171 FAILED THIS IGN, condition is not present. Go to TROUBLE SHOOTING - NO CODES article.
  5. Check vacuum hoses for splits, kinks and proper routing. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  6. Check PCV valve for proper installation. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  7. Start engine. If high or unsteady idle condition exists, go to next step. If idle is okay, go to step  10.
  8. Using scan tool, read IDLE AIR CONTROL value. If value is more than 5 counts, go to step  10. If value is 5 counts or less, go to next step.
  9. Check throttle body, intake manifold, and EGR valve for vacuum leaks. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  10. Check IAC valve for proper operation. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  11. Check for fuel contamination. If fuel is contaminated, repair condition causing contamination. Retest system. If fuel is okay, go to next step.
  12. Check PCM injector, power and sensor grounds for clean and tight connection, and for proper location. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  13. Perform fuel system pressure test. See FUEL PUMP PRESSURE TEST under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  14. Ensure evaporative system is functional. See DTC P0443: EVAP SYSTEM PURGE CONTROL VALVE CIRCUIT MALFUNCTION . If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  15. Check intake manifold, injector "O" rings, EGR adapter, EGR valve, and EGR feed pipes for vacuum leaks. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  16. Check exhaust system for leaks, loose or missing hardware. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  17. Perform FUEL INJECTOR BALANCE TEST under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  18. Ensure HO2S is installed securely, and connector and harness are not contacting exhaust manifold or ignition wires. If a problem is found, repair as necessary. Retest system. If no problem is found, go to DIAGNOSTIC AIDS .
scientia non olet · About LEMON Manuals