DTC P0505: Idle Control System Malfunction
NOTE:
If DTC P1508 is set with DTC P0505, trouble shoot DTC P1508 first, then recheck for DTC P0505.
- Start engine. Hold engine speed at 3000 RPM under no load condition with transaxle in Neutral or Park until radiator fan comes on. Allow engine to idle. Using scan tool, check engine speed with no load (headlights, blower motor, rear defogger, radiator cooling fan and A/C off). If engine speed is less than 650 RPM, go to next step. If engine speed is not less than 650 RPM, go to step 3 . If engine speed is 650-750 RPM, problem is intermittent. System is okay at this time.
- With engine idling, disconnect Idle Air Control (IAC) valve 2-pin harness connector. If engine speed increases or fluctuates, check and adjust idle speed. See ON-VEHICLE ADJUSTMENTS article. If idle speed cannot be set, clean throttle body ports. If engine speed does not increase or fluctuate, replace IAC valve.
- Turn ignition off. Remove intake air duct from throttle body. Start engine and allow it to idle. Place a finger on lower port in throttle body. See Fig 1 . If engine speed does not decrease, go to next step. If engine speed decreases, check engine coolant level and for air in cooling system. If cooling system is okay, replace fast idle thermo valve.
- Place a finger on upper port in throttle body. If engine speed does not decrease, check for vacuum leaks and ensure throttle valve is completely closed. Repair as necessary. If idle speed decreases, adjust base idle speed to specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS article. If idle speed will not adjust to specification, replace IAC valve. Perform final procedure. See FINAL PROCEDURE .