P1506Manufacturer-specific code

P1506 Code: Idle Air Control Overspeed Error (Ford)

On Ford, Lincoln and Mercury vehicles, the P1506 code means the idle air control system has an overspeed error: the engine idles higher than the target. The check engine light comes on. Other brands may define this number differently.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$10 to $200
Difficulty
Easy
System
Idle and Speed Control
Applies to
Depends on the manufacturer

Common in: Ford

Updated Reviewed by Renzo Chacca

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What the P1506 code means

P1506 is a manufacturer-specific code: the 1 in the second position means each automaker defines what it means, not the generic SAE standard. The most widespread definition is the one used by Ford, Lincoln and Mercury. If your vehicle is another brand, confirm the code text with a scan tool that supports that manufacturer.

ManufacturerMeaning of P1506
Ford, Lincoln and MercuryIdle air control overspeed error

The IAC valve regulates the air that enters with the throttle closed in order to hold the idle. The computer compares the actual engine speed with the target.

The computer sets the P1506 code when idle is higher than the target and it cannot bring it down. It is usually caused by a vacuum leak or a throttle that does not close.

Before you start repairs, confirm the make, model, year and engine. With manufacturer codes, the same number can change even between engines from the same brand.

P1506 code symptoms

  • High idle.
  • Check engine light on.

Likely causes of the P1506 code

  1. Vacuum leak. Confirm it with the tests in the diagnosis section.
  2. Throttle that does not close because of dirt or a tight cable.
  3. IAC valve stuck open. Check it by commanding it with the scan tool.

How to diagnose the P1506 code step by step

  1. Look for vacuum leaks at hoses, the intake boot and the manifold gasket.
  2. Clean the throttle and the IAC valve.
  3. Check the throttle cable for tension and free movement.

How to fix the P1506 code

  • Repair the leak.
  • Clean or replace the IAC valve.
  • Adjust the cable.

Technical reference data

  • Typical warm idle: 650 to 850 rpm.
  • P1xxx codes are manufacturer-specific: confirm the definition with a scan tool that supports your brand.
  • Reference values: check the manufacturer data for your vehicle.

Brand-specific notes

A high idle on a warm engine almost always comes down to extra air getting in somewhere it should not, so check for leaks before replacing parts.

P1506 on Ford

Common on the Focus, Fiesta, Escape, Explorer, Ranger, F-150 and Mustang.

If your vehicle is another brand, check the table above for the meaning its manufacturer gives this code and confirm it with a compatible scan tool.

Frequently asked questions about P1506

What does the P1506 code mean on a Ford?
It means the idle air control system has an overspeed error: the engine idles higher than the target. The check engine light comes on.
Does P1506 mean the same thing on every brand?
No. It is a manufacturer-specific code, so on other brands it may not exist or may mean something different. Confirm it with a scan tool that supports your make.
Can I drive with a P1506 code?
Yes. With a P1506 code severity is low and the vehicle normally drives as usual. The high idle can feel annoying and wastes some gas.
How much does it cost to fix P1506?
Roughly $10 to $200 on a Ford. A vacuum hose or a cleaning is cheap, while a new IAC valve costs more.
Will a P1506 code clear itself?
Not while the extra air is still getting in. After the leak or the sticking part is fixed and the code is cleared, it should stay off.
What is the most common cause of P1506?
A vacuum leak or a throttle that does not close. An IAC valve stuck open is the next thing to check.

Related codes

Questions about the P1506 code

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