DTC P0505: Idle Control System Malfunction
NOTE:
Trouble shoot DTC P1508, if set at same time, before proceeding.
- If DTC P0505 is set, check the following:
- IAC valve mechanical malfunction.
- Fast idle thermo valve malfunction.
- Clogged throttle body port or improper adjustment.
- Intake manifold or manifold gasket leak.
- Intake air hose loose or leaking.
- Vacuum hose leaks.
- Incorrect ECT sensor signal.
Repair as necessary. If no problems are found, go to next step.
- Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral, until radiator fan comes on. Allow engine to idle. Using scan tool, check idle speed data under no-load conditions (all accessories off). See IDLE SPEED SPECIFICATIONS . If idle speed is within specification, problem is intermittent, system is okay at this time. If idle speed is less than minimum specification, go to next step. If idle speed is more than maximum specification, go to step 4).IDLE SPEED SPECIFICATIONS
Application RPM 3.2TL 590-690 - Disconnect IAC valve 2-pin connector. If engine speed drops or engine stalls, adjust base idle speed. If base idle speed cannot be adjusted, clean ports in throttle body. If engine speed does not drop, replace IAC valve.
- Turn ignition off. Remove cover from fast idle thermovalve. See Fig 1. Start engine and allow to idle. Feel for airflow at valve seat. If airflow does not exist in valve seat area, go to next step. If airflow exists in valve seat area, check coolant level and for air in cooling system. If okay, replace fast idle thermovalve.
- Check for vacuum leaks and ensure throttle valve is fully closed. Adjust idle speed. If idle speed cannot be adjusted, replace IAC.NOTE: After removing and replacing fast idle thermovalve cover, perform PCM reset procedure. See procedures under PCM RESET PROCEDURE/CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.