P1507Manufacturer-specific code

P1507 Code: Idle Air Control Underspeed Error (Ford)

On Ford, Lincoln and Mercury vehicles, the P1507 code means the idle air control system has an underspeed error: the engine idles lower than the target. The check engine light comes on. Other brands may define this number differently.

Severity
Medium
Can I keep driving?
Yes, but with caution
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 P1507 code means

P1507 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 P1507
Ford, Lincoln and MercuryIdle air control underspeed 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 P1507 code when idle is lower than the target. It is almost always a dirty IAC valve or a dirty throttle.

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.

P1507 code symptoms

  • Low idle or an engine that stalls.
  • Check engine light on.

Likely causes of the P1507 code

  1. Dirty IAC valve. The most frequent cause.
  2. Throttle with carbon buildup. Confirm it with the tests in the diagnosis section.
  3. Clogged air filter. Check the airflow into the engine.
  4. Failed IAC valve. Confirm it with the tests in the diagnosis section.

How to diagnose the P1507 code step by step

  1. Clean the IAC valve and the throttle.
  2. Measure the IAC resistance. The Ford spec is 6 to 13 ohms.
  3. Check the air filter for blockage.

How to fix the P1507 code

  • Clean or replace the IAC valve.

Technical reference data

  • Ford IAC valve resistance: 6 to 13 ohms.
  • 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

Cleaning comes first here. A stalling idle can leave you stuck at a light, so do not put this one off for long.

P1507 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 P1507

What does the P1507 code mean on a Ford?
It means the idle air control system has an underspeed error: the engine idles lower than the target. The check engine light comes on.
Does P1507 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 P1507 code?
With caution. A P1507 code can make the engine stall, which is a safety concern at intersections, so get it fixed soon.
How much does it cost to fix P1507?
Roughly $10 to $200 on a Ford. Cleaning the IAC valve and throttle is cheap, while a new IAC valve costs more.
Will a P1507 code clear itself?
Not while the valve or throttle is still dirty. After cleaning or replacing the part, clear the code and confirm the idle is steady.
What is the most common cause of P1507?
A dirty IAC valve. Carbon on the throttle and a clogged air filter are the next things to check.

Related codes

Questions about the P1507 code

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