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Home >> Isuzu >> 2000 >> Rodeo LS, 2.2 D >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Trouble Code Identification >> DTC P0507: IAC System Rpm High >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic II (OBD-II) system check. See SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
  2. Using scan tool, read DTCs. If any other DTCs are set, diagnose affected DTCs before proceeding. If no other DTCs are set, go to next step.
  3. Start engine. Turn all accessories off. Using scan tool, monitor ENGINE SPEED and command engine speed up to 1500 RPM, down to 500 RPM, and back up to 1500 RPM. If ENGINE SPEED remains within 50 RPM of desired RPM for each command, go to DIAGNOSTIC AIDS . If ENGINE SPEED is not as specified, to next step.
  4. Disconnect IAC harness connector. Install IAC Noid Light (J37027) in IAC harness connector. Monitor noid lights while commanding engine speed up to 1500 RPM, down to 500 RPM, and up to 1500 RPM. Both noid lights should cycle Green and Red, but not OFF as RPM changes from 500 to 1500 RPM. If lights flash as specified, go to step  6. If lights do not flash as specified, go to next step.
  5. Check IAC "A" low and IAC "A" high, and IAC "B" low and IAC "B" high circuits for open or shorted condition. If such a condition is found, repair as necessary. Retest system. If no problem is found, go to step  9.
  6. Check for vacuum leaks. Ensure throttle stop screw has not been tampered with. Check for throttle plate or shaft binding. Check accelerator and cruise control cables for misadjustment or binding. Check for faulty, missing or incorrectly installed PCV valve. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
  7. Check for faulty connection at IAC harness connector. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  8. Using a DVOM, check IAC valve solenoids for an open, short to ground or shorted together condition. If such condition exists, go to next step. If no problem is found with IAC valve solenoids, go to step  10.
  9. Replace IAC valve. Retest system.
  10. Replace and reprogram PCM using required equipment. See PROGRAMMING . Retest system.
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