DTC P0505: Idle Control System
NOTE:
Possible causes of DTC P0505 are IAC valve, fast idle thermovalve, clogged port in throttle body, vacuum leaks, incorrect signal from ECT sensor, and incorrect signal from TP sensor.
- Connect and operate scan tester, following manufacturer's instructions. Run engine at 3000 RPM until fan comes on, then allow it to idle. Read Throttle Position (TP) data. Throttle position should be approximately 10 percent. Read Engine Coolant Temperature (ECT) data. Engine coolant temperature should be 194-221°F (90-105°C). If TP and ECT data is within specification, go to next step. If TP or ECT data is not within specifications, repair appropriate sensor circuit.
- Read idle speed data under no-load conditions (all accessories off). See IDLE SPEED SPECIFICATIONS
. If idle speed is within specification, problem is intermittent, and system is okay at this time. If idle speed is less than minimum specification, go to next step. If idle speed is greater than maximum specification, go to step 4).IDLE SPEED SPECIFICATIONS
Application Specification 2.5TL 650-750 RPM - Unplug 2-pin connector from IAC valve. If engine speed drops or engine stalls, adjust base idle speed. If base idle speed cannot be adjusted, clean ports at throttle body. If engine speed does not drop, temporarily substitute known good IAC valve, then retest system.
- Turn ignition off. Remove cover from fast idle thermo valve. See Fig 1 . Start and idle engine. 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 all is okay, temporarily substitute known good fast idle thermo valve, then retest system.
- Inspect for vacuum leaks. Ensure throttle valve closes fully. Adjust idle speed. If idle speed cannot be adjusted, temporarily substitute known good IAC, then retest system.