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Diagnosis & Repair

  1. Check air intake hose between throttle body and cylinder head. Check for loose, damaged or cracked hose. Repair as necessary. If air intake hose is okay, go to next step.
  2. Disconnect ECM E7 connector. See Figure. Disconnect A/C control assembly 16-pin connector. Check continuity of Black/Yellow wire between terminal No. 16 at ECM E7 connector and A/C control assembly 16-pin connector. If continuity exists, go to next step. If continuity does not exist, repair open Black/Yellow wire and retest system.
  3. Measure resistance between ground and terminal No. 16 (Black/Yellow wire) at ECM E7 connector. If resistance is 5 ohms or more, reconnect connectors and go to next step. If resistance is less than 5 ohms, repair short to ground in Black/Yellow wire and retest system.
  4. Access ECM behind glove box. Turn ignition off. Disconnect ECM E10 connector. See Figure. Turn ignition on. Using DVOM, measure voltage between ground and terminals No. 22 (Yellow/Black wire) and No. 23 (Red/White wire) at ECM E10 connector. If both readings are 9-14 volts, go to step 6). If any reading is not 9-14 volts, go to next step.
  5. Disconnect IAC valve connector. Measure resistance between Black/Yellow wire terminal and Red/Black and Yellow/Black wire terminals at IAC valve. Resistance should be 17-25 ohms (cold) or 22-29 ohms (hot). If both readings are as specified, check for open or short circuit in wiring harness between IAC valve and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If any reading is not as specified, replace IAC valve.
  6. Check IAC valve operation. See IDLE CONTROL SYSTEM in SYSTEM/COMPONENT TESTS article. Replace IAC valve as necessary. If IAC valve is okay, replace ECM and retest system.
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