Idle Speed: Testing and Inspection

1. When the idle speed is out of specification and the Malfunction Indicator Lamp (MIL) does not blink Diagnostic Trouble Code (DTC) 14, check the following items:
^ Adjust the idle speed.
^ Air conditioning signal
^ Alternator FR signal
^ A/T gear position signal
^ Starter switch signal
^ Brake switch signal
^ PSP switch signal
^ Fast idle thermo valve.
^ Starting Air Valve
^ Hoses and connections
^ IAC Valve and its mounting 0-rings

2. If the above items are normal, substitute a known-good IAC Valve and readjust the idle speed.
^ If the idle speed still cannot be adjusted to specification (and the MIL does not blink code 14) after IAC Valve replacement, substitute a known-good ECM and recheck. If symptom goes away, replace the original ECM.