LEMON Manuals: Even more car manuals for everyone
Home >> Honda >> 2000 >> CR-V SE, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 10 (Engine Controls - Self-Diagnostics - 4.3L) >> Diagnostic Trouble Code Identification >> DTC P1508: IAC System Low Rpm, & DTC P1509: IAC System High Rpm >> 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 SELF-DIAGNOSTICS - INTRODUCTION article. Retrieve and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. Turn ignition off. Ensure Tech 2 scan tool is installed. Connect IAC driver to IAC valve. Set parking brake, brake drive wheels and turn A/C off. Start engine and allow it to idle in Park (A/T) or Neutral (M/T). Using scan tool, read engine speed (RPM). Using IAC driver, extend and retract IAC valve. If engine RPM decreases and increases as IAC valve is cycled, go to next step. If engine RPM does not change, go to step  4.
  3. If engine speed changes smoothly from 700 RPM to 1500 RPM, go to step  5. If RPM does not change smoothly, go to next step.
  4. Check IAC valve passage. If passage is not okay, clean passage and go to step  12. If passage is okay, replace IAC valve. Disconnect negative battery cable for 10 seconds, then reconnect cable. Turn ignition on, engine off for 5 seconds. Turn ignition off for at least 10 seconds and go to step  12.
  5. Install IAC Node Light (J37027-A) in VCM harness. Cycle IAC driver and note lights. Both lights should cycle Green and Red, but not OFF as RPM changes from 700 RPM to 1500 RPM. If lights flash as specified, go to step  8. If lights do not flash as specified, go to next step.
  6. Check for faulty connector terminal contacts, open circuits, short to ground or voltage, or faulty VCM connection. If problem is found, go to next step. If no problem is found, go to step  11.
  7. Repair connection, terminal contact or circuit as necessary. After repairs, go to step  12.
  8. Using other connector on IAC driver pigtail, check resistance across IAC valve coils. Check resistance of IAC coil "B" HI circuit (Light Green/White wire) and LO circuit (Light Green/Black wire). Check resistance of coil "A" HI circuit (Light Blue/White wire) and LO circuit (Light Blue/Black wire). If resistance on both coils is 40-80 ohms, go to next step. If resistance is not as specified on both coils, go to step  10.
  9. Check resistance between coil "B" HI circuit (Light Green/White wire) and coil "A" LO circuit (Light Blue/Black wire). Check resistance between coil "B" LO circuit (Light Green/Black wire) and coil "A" HI circuit (Light Blue/White wire). Resistance should be infinite. If resistance is as specified between both coils, see DIAGNOSTIC AIDS . If resistance is not as specified, go to next step.
  10. Replace IAC valve. Disconnect negative battery cable for 10 seconds, then reconnect cable. Turn ignition on, engine off for 5 seconds. Turn ignition off for at least 10 seconds. After repairs, go to step  12.
  11. Replace VCM. Program replacement VCM. See PROGRAMMING . After replacing VCM, go to next step.
  12. Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P1508. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step  2.
  13. Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.
scientia non olet · About LEMON Manuals