P0507 OBD-II: Idle Air Control System RPM Higher Than Expected

OBD II Fault Code

• OBD II P0507

Fault Code Definition

• Idle Control System RPM higher than expected

The purpose of the Idle Control System is to manage the engine idle speed to meet the ever-changing loads placed on the engine, such as the use of air conditioning, heater blower motor, wipers etc.

Code P0507 sets when the idle speed is persistently above a pre-determined RPM level for a specified amount of time.

P0507 Symptoms

• Check Engine Light will illuminate
• Engine idle speed is very high
• Engine idles rough
• In some cases, the engine may idle erratically

Common Problems That Trigger the P0507 Code

• Defective/sticking Idle Air Control Motor
• Intake Manifold Vacuum leaks
• Carbon buildup in the Throttle Body air passages
• Defective Coolant Temperature Sensor
• Defective Charging System/Alternator
• Defective Power Steering Pressure Switch

Common Misdiagnosis

• Idle Air Control Motor is replaced when code P0507 was triggered by carbon buildup in the Throttle Body air passages and/or the Idle Air Control Motor.

Want to learn more?

The idle speed is often controlled by an Idle Air Control Motor mounted on or near the Throttle Body of the Intake Manifold. In earlier vehicles, an Idle Air Stepper Valve or Motor is used. After the model year 2000, more vehicles began to use a 'drive by wire system', whereby the Idle Air System is incorporated into the assembly of the Electronic Throttle Body. With any of the above systems, to raise or lower the engine Idle speed, the Powertrain Control Module (PCM) allows more or less air into the engine.

P0507 Diagnostic Theory for Shops and Technicians

When inspecting for the cause of an idle air control malfunction, I start by looking at the freeze frame data to get a picture of when the malfunction occurred. I also test the basic functionality of the system by turning the steering wheel as if were parking the vehicle while the vehicle is stopped and the engine is idling. This should energize the system and boost the idle rpm so the engine does not stall during the higher engine load, caused by the power steering pump working at or near maximum output. I pay close attention to the data stream to verify that higher rpm is requested and that the system system is responding. In addition to the above inspections I open up the throttle body and look at the throttle blade to see if it's clean or full of carbon.