P0506

DTC P0506: Idle Control System RPM Lower Than Expected

NOTE: if DTC P0511 is stored at the same time as DTC P0506, troubleshoot DTC P0511 first, then recheck for DTC P0506.

1. Start the engine. Hold the engine at 3,000 rpm with no load (in neutral) until the radiator fan comes on, then let it idle.
2. Check the engine speed at idle with no-load conditions: headlights, blower fan, radiator fan, and air conditioner off.

If the engine running at 800 ± 50 rpm?

YES - Intermittent failure, system is OK at this time.

NO - Go to step 3.

3. Turn the ignition switch OFF.
4. Disconnect the IAC valve 3P connector.
5. Start the engine, and let it idle.
Check the engine speed at idle with no-load conditions; headlights, blower fan, radiator fan, and air conditioner off.

Does the engine speed increase or fluctuate?

YES - Check the idle speed with a different load condition (electrical, A/C, etc.). If it's out of specification, replace the IAC valve.

NO - Replace the IAC valve.