LEMON Manuals: Even more car manuals for everyone
Home >> Honda >> 2000 >> CR-V SE, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 7 (Engine Controls - Self-Diagnostics - 2.2L) >> Diagnostic Trouble Code Identification >> DTC P0171: Fuel Trim System Lean >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2000 Isuzu Hombre. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform On-Board Diagnostic II (OBD-II) system check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in SELF-DIAGNOSTICS - INTRODUCTION article. After performing OBD-II system check, go to next step.
  2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
  3. Start and warm engine to normal operating temperature. Ensure system is in closed loop. Using scan tool, select FUEL TRIM INDEX. If fuel trim index is less than 160, go to next step. If fuel trim index is 160 or greater, go to step  5.
  4. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data, and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If fuel trim index is 160 or less, go to step  16. If fuel trim index is greater than specification, go to next step.
  5. Check vacuum hoses for splits, kinks and proper routing. Check PCV valve for proper installation. Check for fuel contamination. Check PCM and sensor grounds. Check O2S 1 for correct installation and ensure O2S 1 wiring is not in contact with exhaust manifold. If no problems are found, go to next step. If any problem is found, go to step  7.
  6. Disconnect MAP sensor connector. Operate vehicle in closed loop while monitoring FUEL INDEX TRIM. If fuel trim index is 160 or less, go to step  15. If fuel trim index is 161 or greater, go to step  9.
  7. Repair fault that was detected in step  5. Operate vehicle in "closed-loop" while monitoring FUEL INDEX TRIM. If fuel trim index is less than 160, go to next step. If fuel trim index is greater than 160, go to step  9.
  8. Lean condition is not present at this time. If a driveability problem exists, go to TROUBLE SHOOTING - NO CODES article. If no driveability problem exist, go to step  16.
  9. Check vacuum hoses for splits, kinks and proper routing. Check throttle body, intake manifold and injector "O" rings for vacuum leaks. Repair as necessary. After repairs, go to step  16. If no repairs are necessary, go to next step.
  10. Start engine and allow it to idle. Using scan tool, check IAC count. If IAC count is greater than 5, go to next step. If IAC count is 5 or less, go to step  12.
  11. Check for fuel contamination. Repair as necessary. After repairs, go to step  16. If fuel is okay, go to step  13.
  12. Go to DTC P0506: IAC SYSTEM RPM LOW  or DTC P0507: IAC SYSTEM RPM HIGH  to check IAC valve performance. Repair as necessary. After repairs, go to step  16. If IAC valve is okay, go to next step.
  13. Connect a fuel pressure gauge to fuel system. Cycle ignition switch 2-3 times. With fuel pump running, observe fuel pressure. If fuel pressure is 41-47 psi (2.9-3.3 kg/cm2 ), go to next step. If fuel pressure is not 41-47 psi (2.9-3.3 kg/cm2 ), repair fuel system as necessary. See SYSTEM & COMPONENT TESTING article.
  14. Ensure engine is at normal operating temperature. Start engine and let idle. Observe fuel pressure. Fuel pressure noted in step  13 should drop 3-10 psi (.21-.70 kg/cm2 ). If fuel pressure is as specified, perform injector balance test. See FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If fuel pressure is not as specified, see FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.
  15. Replace MAP sensor. After repair is completed, go to next step.
  16. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, then enter DTC P0171. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step  2.
  17. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time. See DIAGNOSTIC AIDS .
scientia non olet · About LEMON Manuals