Diagnostic Aids

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

With the engine idling at a normal operating temperature and all accessories OFF, monitor the following parameters on the scan tool for correct operation:

The IAC Motor Command-25-45 percent
The electrical load-No
The commanded A/C-OFF

The scan tool can be used to isolate the cause of an intermittent DTC P0505. Engine idle speed can be controlled with the scan tool. Operate the IAC valve with the scan tool while checking for a smooth increase and decrease in engine speed. If engine speed can be controlled, the IAC system is functioning normally.

Check for the following conditions:

Any blockage of the air intake system
Any blockage of the IAC passage
Excessive deposits on the throttle plate or the throttle bore
Any large vacuum leaks

An intermittent malfunction may be caused by a fault in the IAC sensor electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions .

Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.

The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

If the DTC P0505 does not reset, but a driveability symptom still exists, refer to Symptoms - Engine Controls .