AF - High Idle/Low Idle

Description
This describes the operations necessary to diagnose a High Idle/Low Idle symptom. This will involve checking the Air, ECM, and other systems.
Refer to "Symptom Matrix Chart" for details.

Diagnostic Repair Procedure
Check the following:
1. Battery and Alternator
2. Fuel quality
3. Air intake leaks
4. Base Idle speed, ignition timing and throttle position sensor adjustment: BASIC INSPECTION AND ADJUSTMENT
5. Target idle speed: Spec = 625 ± 50 RPM (A/T)/700 ± 50 RPM (M/T)
6. IACV-AAC Valve operation: Use CONSULT-II, ENGINE -ACTIVE TEST -IACV-AAC/V OPENING
7. IACV-FICD operation
8. Fuel Pump and Fuel Pressure Regulator operation: Gauge should read 34 psi at idle and 43 psi when fuel pressure regulator vacuum hose is disconnected and plugged.
9. EGR: Confirm that it is not stuck open or leaking exhaust into the intake manifold.

Use CONSULT-II to check the operation of the following items:
10. P0100 - MASS AIR FLOW SENSOR
11. P0131 - FRONT HEATED OXYGEN SENSOR
12. P0125 - ENGINE COOLANT TEMPERATURE SENSOR
13. P0120 - THROTTLE POSITION SENSOR

Other items to be checked as possible malfunction cause
14. PCV system
15. EVAP system
16. A/C circuit
17. Oil level and condition
18. ECM