P0511

DTC P0511: Idle Air Control (IAC) Valve Circuit Malfunction

General Description
The target idle speed is in the engine control module (ECM)/powertrain control module (PCM) memory for various engine conditions (coolant temperature, A/C operation, and other functions). The ECM/PCM keeps the actual idle speed at the target idle speed by switching the idle air control (IAC) valve ON/OFF to control the intake airflow. In addition, the IAC valve functions as the fast idle valve to control the speed according to the engine coolant temperature. If the duty cycle signals are not input to a circuit that checks return signals in the ECM/PCM, a malfunction is detected and a DTC is stored.




Monitor Execution, Sequence, Duration, DTC Type, OBD Status




Enable Conditions

Malfunction Threshold
The return circuit did not receive the duty signals from the ECM/PCM for at least 5 seconds.

Diagnosis Details

Conditions for illuminating the MIL
When a malfunction is detected, the MIL comes on and the DTC and the freeze frame data are stored in the ECM/PCM memory.

Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the diagnostic runs.

The MIL, the DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.