Error Code P1506 – Symptoms, Causes and Solutions.

The error code P1506 is defined as an overspeed error in idle air control. This code means that the engine idle is outside factory specifications


This error code is a manufacturer-specific trouble code, which means that Does not apply to all vehicle brands. Rather, it applies only to specific vehicle brands, such as Ford. Definition specification, troubleshooting, and repairs still vary from one make and model to another.

Error Code P1506 Definition

The whole IACV valve o Idle air control valve works by controlling the engine idle speed and providing a dashpot function. valve assembly IAC It measures the intake air around the throttle plate through a bypass inside the IAC valve assembly and throttle body.

The PCM (powertrain control module, also known as ECM or engine control module) determines the desired idle speed or bypass air and sends a signal to the valve assembly IAC through a specific work cycle.

Reads: P2302 OBD Error Code – Ignition Coil Secondary Circuit “A”

The IAC valve It then responds by positioning itself to control the amount of air diverted. The PCM monitors the engine RPM and increases or decreases the IAC duty cycle so that it reaches the RPM desired.

The error code P1506 is set when the PCM detects an engine idle speed that is outside the specifications (higher RPM) set by the manufacturer. Sometimes the IAC can have a carbon buildup.

Common symptoms

Like other error codes, this error code activates the light Check Engine and registers the code in the system.

Possible causes

Possible causes of this code include:

  • Defective idle air control (IAC) valve
  • IAC valve harness open or shorted
  • Poor electrical connection in the IAC valve circuit
  • Intake leaks
  • Stuck PCV valve

What happens if the IAC is disconnected?

If it works properly, stopping it would cause panic to your idling engine. Normally, if you start your car, the idle air control valve will increase and decrease the engine rpms slowly.

How do you relearn a Ford throttle body?

To “relearn” the Ford Fusion throttle body, move the car to a flat surface, set the parking brake, and put the shift lever in park. Turn off all accessories. Start the engine and run it until it reaches operating temperature and let it idle for at least 1 minute.

Can a bad MAF sensor cause high idle?

If the MAF sensor is bad or disconnected, the engine computer will use a default programmed strategy to control fuel flow. That can result in a high idle rate.

What controls engine idle speed?

Idle speed is controlled using an electronically controlled throttle bypass valve, as seen in Fig. 6.6, which allows air to flow around the throttle plate and produces the same effect as if the throttle had been opened slightly. so that there is enough flow to keep the engine running.

How to check it

The first thing to do is help the vehicle relearn idling. You can do this by disconnecting the battery, removing the valve, cleaning and reinstalling the valve, and then driving the vehicle for about 5 minutes with the headlights and air conditioning on to let the vehicle relearn idle.

Also, check for intake leaks or a stuck PCV valve.

How to fix

It is important not to start with an idle air control (IAC) valve replacement when you have this code, because in many cases the problem is caused by too many vacuum leaks, and can cause serious idling problems.

Air leaks into the engine after the MAF has already measured the incoming air, causing the O2 (oxygen) sees a very poor exhaust. As the vehicle is idling, the computer will attempt to reduce the incoming air by closing the IAC. When it orders less air, and the vehicle continues at high idle, it will set the error code.

In this case, the usual cause of the problem is air leaks in the rubber hose. Begin your diagnosis by replacing both the PCV and hose. Many people report that their vehicle does not stop with this hose.

If the problem persists, then you need to replace the IAC valve.

If you want to know other articles similar to Error Code P1506 – Idle Air Control Overspeed Error you can visit the category Fault Codes.


Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *