Idle Control System

TROUBLESHOOTING GUIDE

Idle Control System / Troubleshooting:

NOTE:
- Across each row in the chart, the sub-systems that could be sources of a symptom are ranked in the order they should be inspected, starting with "1". Find the symptom in the left column, read across to the most likely source, then refer to that source listed at the top of that column. If inspection shows the system is OK, try the next system "2", etc.

- If the Idle Speed is out of specification and the Malfunction Indicator Lamp (MIL) does not blink Diagnostic Trouble Code (DTC) 14, go to inspection described in Idle Control System/Description.

HINT:
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.
Automatic Transmission (A/T) Gear Position Signal.
Brake Switch Signal (Except Canada M/T).
Starter Switch Signal.
Power Steering Pressure (PSP) Switch Signal.
Fast Idle Thermo Valve.
Hoses and Connections.
IAC Valve and its mounting 0-Rings.

If the above items are normal, substitute a known-good IAC Valve and re-adjust the idle speed.

If the idle speed still cannot be adjusted to specification land 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.