P0505
DTC P0505: Idle Control System MalfunctionNOTE: If DTC P1519 is stored at same time as DTC P0505, troubleshooting DTC P1519 first, then recheck for DTC P0505.
1. Start the engine. Hold the engine at 3,000 rpm with no load (in Park or 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, rear window defogger, radiator fan, and air conditioner are not operating.
Is the engine running at 730 ± 50 rpm?
YES - Intermittent failure, system is OK at this time.
NO - If the idle speed is less than 680 rpm, go to step 3; if it's 780 rpm or higher, go to step 4.
3. Disconnect the idle air control (IAC) valve 3P connector.
Does the engine speed increase or fluctuate?
YES - Adjust the (base) idle speed. If it's impossible, clean the ports in the throttle body.
NO - Replace the IAC valve.
4. Turn the ignition switch OFF.
5. Remove the intake air duct from the throttle body.
6. Start the engine and let it idle.
7. Put your finger on the lower port (A) in the throttle body.
Does the engine speed drop below 780 rpm?
YES - Adjust the idle speed. If it's impossible, replace the IAC valve.
NO - Check for vacuum leaks. Make sure the throttle valve is completely closed, and repair as necessary.