P0506: Idle Air Control System RPM Lower Than Expected

What does the P0506 error code mean?

The P0506 check engine error code means that the Idle Air Control System RPM is lower than expected. The code is triggered when the engine control module detects that your engine's idle speed is lower than the programmed threshold. That speed is measured by either the idle air control system or by the electronic throttle control on newer vehicles. The latter system adjusts how much air is allowed into the engine when the throttle is closed. 

Why is this issue important?

If the idle speed is too low, it can cause a couple of issues. It could cause the engine to stall when you're coming to a stop. It could also cause systems like air conditioning to operate less efficiently, making drivability poor, increasing engine wear and reducing fuel efficiency. 

Can I safely drive my car with this error code?

In the short term, probably. However, driving with this code is not recommended because the engine may stall, which could cause a safety issue. It can also increase engine wear and make your fuel economy worse. 

Common symptoms of the P0506 error code

Some common symptoms of the P0506 error code include the engine stalling at idle, running rough, an illuminated check engine light, and difficulty starting the engine. It can also cause poor acceleration from a stop and can negatively impact fuel economy. 

How is the P0506 error code diagnosed?

You can use an OBD scanner tool to retrieve and confirm the error code. You can also take your vehicle to a trusted mechanic, who can analyze it, particularly the rpm (revolutions per minute) and idle control system. 

Other things to do include checking intake hoses and gaskets for air leaks, testing your vehicle's electrical system, and checking wires and connectors to ensure they aren't damaged. 

How is the P0506 error code repaired?

You may be able to clean the throttle body and idle air control valve to get them back in working order. If that doesn't work, you may need to repair or replace the idle air control valve. You can also address any damaged hoses, gaskets or electrical equipment. 

Related reading

If you have other error codes you'd like to research, check out Edmunds' library of OBD-II Diagnostic Trouble Codes.