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P0511 is a diagnostic trouble code (DTC) for "Idle Air Control Circuit". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
This DTC represents Idle Air Control Circuit, indicating an abnormal condition in the RPMs when the engine is idling.
Each vehicle idles at a manufacturer specified RPM level. The PCM (powertrain control module) monitors the idle RPM to ensure that it falls within the expected parameters. If it doesn’t, then the PCM will attempt to return the RPMs to normal. Failing this, the DTC will set.
The most common cause of this DTC is when the throttle body bore has carbon/coke buildup. Other possibilities include:
The Malfunction Indicator Lamp (MIL) will likely come on, and the trouble code will be stored in the vehicle’s computer. In addition, you may notice high or low RPMs when the engine is idling, stalling at low speed, or intermittent stalling when the throttle is released.
Diagnosing this condition may involve:
Hooking the vehicle up to a scanner to record the data and identify any concurrent fault codes
Clearing the DTCs out of the vehicle’s computer then road testing the vehicle to see if they return (in order to identify an intermittent condition)
Visually inspecting the IAC wiring and connectors for damage or loose connections
Using a scanner to manually open the IAC motor then testing the IAC motor connector voltage
Inspecting the throttle body for coking and carbon buildup (coke will appear as a greasy black substance)
Sometimes idle air control parts will be replaced without making sure the throttle body is not restricted. In attempting to repair the problem, throttle body cleaning can be an option, but more often than not the required chemicals damage the surrounding wiring and connectors. Replacement is usually the better option.
This fault is more than a convenience issue, due to the fact that the vehicle may not even be drivable. It is possible, however, that the car could stall unexpectedly, leaving you in a difficult or even unsafe situation. It’s best to have the problem looked at and repaired as soon as possible.
Fixing an idle air control circuit malfunction may involve:
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6220.