# P0507: Idle Air Control System RPM Higher Than Expected

**Verdict:** Safe to drive

Speed and idle control - Generic OBD-II code, applies to all gasoline cars and light trucks sold in the US since 1996.

- **Typical cost:** $80-$900
- **Urgency:** Keep driving
- **Most likely:** Vacuum leak
- **DIY?:** Steps 1-2

## Quick answer

P0507 means the engine is idling faster than the computer is trying to make it idle, even after it has closed the idle air control as far as it can. Extra air is getting into the engine from somewhere the computer cannot control, most often a vacuum leak. A sticking idle air control valve or throttle can also cause it.

## What does P0507 mean?

At idle, the engine computer sets engine speed by controlling how much air slips past the closed throttle, using a separate idle air control (IAC) valve on older engines or tiny movements of an electronic throttle plate on newer ones. Every other path air can take into the engine, such as the PCV system and the brake booster hose, is supposed to be accounted for and sealed.

P0507 sets when idle speed stays above the target by more than an allowed amount, even though the computer has already cut idle air as far as it can. Because it cannot close the gap, the computer concludes that air is getting in some other way. The test runs with the engine warm and the vehicle stopped. Thresholds vary by maker, and most cars need two failed drive cycles before the check engine light comes on.

## What are the symptoms of P0507?

- High idle, often 1,000 RPM or more when warm
- Car creeps forward strongly at stops
- Idle surges up and down
- Check engine light on

## What causes P0507?

Ranked from most to least likely. Check them in this order: the cheap, common causes first.

1. **Vacuum leak** (most common). Rubber vacuum hoses, the PCV valve and its grommet, and intake manifold gaskets harden and crack with heat and age, letting in air the computer cannot meter. Idle rises and may surge. It is most common on older and higher-mileage engines, and you may hear a hiss near the intake with the engine running.
2. **Sticking idle air control valve** (common). On engines with a separate IAC valve, carbon or a failing motor can leave the valve stuck partly open, so it keeps passing air even when the computer commands it closed. Idle may stay high once warm, or hang high briefly after you lift off the gas. Cleaning sometimes frees it, but a worn valve needs replacement.
3. **Throttle plate not closing fully** (less common). If the throttle plate does not return fully closed, extra air slips around it at idle. On cable-operated throttles, a sticky or kinked cable, a binding pedal, or a tampered stop screw can hold it open, so check that it snaps shut when released. On electronic throttles, carbon or a weak return spring can do the same.
4. **Leaking brake booster or its hose** (less common). The power brake booster draws engine vacuum through a large hose and a one-way check valve. A torn booster diaphragm, a cracked hose, or a leaking check valve lets air into the intake just like a vacuum leak. Idle often changes when you press the brake pedal, and a hissing sound from under the dash is a clue.
5. **Idle relearn needed** (rare). Disconnecting or replacing the battery, or cleaning the throttle body, can erase or upset the computer's learned idle air values. Some cars then idle high until they relearn, which may take a few drive cycles or a scan tool procedure. It is rare as a lasting cause, so look for a leak if high idle continues.

## How do you diagnose P0507?

1. Listen for hissing and inspect vacuum hoses, the PCV valve, and the intake for leaks.
2. Have a smoke test done on the intake to find hidden vacuum leaks.
3. Check that the throttle closes fully and the cable (if any) is not binding.
4. Watch idle air control commands with a scan tool. A fully closed command with high RPM confirms extra air.

## How do you fix P0507, and what does it cost?

| Fix | Typical cost | What it involves |
| --- | --- | --- |
| Repair vacuum leak | $100-$450 | Hoses and PCV valves are cheap. Intake gaskets cost more in labor. |
| Clean or replace idle air control valve | $80-$400 | Cleaning may work. Replacement fixes a worn valve. |
| Clean or replace throttle body | $80-$900 | Cleaning is cheap. A new electronic throttle body is at the high end. |

## Is it safe to drive with P0507?

> **Safe to drive.** It is generally safe to drive, but a high idle makes the car push harder against the brakes at stops. Keep a firm foot on the brake and fix it soon if idle is very high.

## Will P0507 fail an emissions test?

A check engine light with P0507 stored fails an OBD-II emissions test in most states. The vacuum leak behind it can also set lean codes and raise emissions in states that still measure tailpipe exhaust. Clearing the code resets the readiness monitors, so repair the leak and drive normally for several days before testing.

## After the repair: clearing P0507

After repairing the leak or cleaning the idle control, clear the code and run any idle relearn your vehicle needs. Warm idle should settle at the normal speed listed in your service manual, and the car should no longer creep hard at stops. If the code stays away for several drive cycles, the repair is done.

## How to prevent P0507

- Replace cracked or hardened vacuum hoses and the PCV valve as they age, before they start leaking.
- Make sure intake ducts and clamps are tight after air filter changes or other engine work.
- Clean the throttle body so carbon does not hold the plate open or jam the IAC valve.
- Do an idle relearn after battery replacement if your service manual calls for one.
- Have a hissing brake pedal checked promptly, since a leaking booster affects both idle and braking.

## P0507 by make

| Make | What to know |
| --- | --- |
| Honda | On many older Honda and Acura engines with a separate idle air control valve, a sticking valve is a frequent cause of high idle and P0507. |

## Codes often seen with P0507

- [P0505](/codes/p0505): Idle Air Control System
- [P0506](/codes/p0506): Idle Air Control System RPM Lower Than Expected
- [P0171](/codes/p0171): System Too Lean (Bank 1)
- [P0174](/codes/p0174): System Too Lean (Bank 2)

## Frequently asked questions

### Can I drive with a P0507 code?

Yes, you can usually drive with P0507. Be careful at stops, because a high idle pushes the car forward against the brakes and can make it lurch when you shift into gear. Repair it soon, especially if idle is well above normal or the car creeps hard at lights.

### What is the most common cause of P0507?

A vacuum leak is the most common cause. Cracked hoses, a failed PCV valve or grommet, and leaking intake gaskets let in extra air that raises idle speed. Shops find hidden leaks fastest with a smoke test, which pushes visible vapor into the intake and shows exactly where it escapes.

### Can disconnecting the battery cause P0507?

It can on some cars, because the computer forgets its learned idle settings when power is cut. Idle may run high for a while after battery work. An idle relearn, or a few normal drive cycles with stops and idling, usually brings idle back to normal. If it does not, look for a leak.

### How much does it cost to fix P0507?

Most P0507 repairs cost $80 to $900. Fixing a vacuum hose, PCV valve, or intake gasket leak runs about $100 to $450 depending on access, cleaning or replacing the IAC valve costs $80 to $400, and a new electronic throttle body is the high end at up to about $900.

### What should my idle speed be?

Many warm gasoline engines idle somewhere around 600 to 800 RPM in park, but your owner's or service manual gives the exact figure for your car. Idle is higher on a cold start and may rise briefly when the AC switches on. A warm idle well above 1,000 RPM points to a problem.

### Can I fix P0507 myself?

Often, yes. Checking and replacing cracked vacuum hoses, a PCV valve, or loose intake clamps needs only basic tools, and cleaning the throttle body is a common DIY job. Hidden leaks under the intake manifold usually need a shop's smoke machine, and some cars need a scan tool for the idle relearn.

### Is a high idle bad for my engine?

A high idle does not usually harm the engine directly, but it wastes fuel and adds wear to brakes and transmission parts because the car pushes against the brakes at stops. Shifting into gear at a high idle can cause a harsh engagement. The vacuum leak behind it can also make the engine run lean.

### Can P0507 come with lean codes?

Yes, because a vacuum leak lets in air that the airflow sensor never measures. The computer adds fuel to compensate, and if the leak is big enough it sets lean codes such as P0171 or P0174. Seeing P0507 together with lean codes makes a vacuum leak very likely.

### Will P0507 fail an emissions test?

Yes, in most states with OBD-II testing, a lit check engine light with P0507 stored is a fail. Clearing the code right before the test does not help, because the readiness monitors reset too. Repair the leak or idle problem, then drive normally for several days so the monitors complete.

### How do I find a vacuum leak at home?

Listen for a hiss around the intake with the engine idling, and look over the vacuum hoses and PCV valve for cracks, splits, or loose ends. Squeezing hoses can reveal brittle spots. Avoid spraying flammable cleaner near a hot engine to find leaks; a shop smoke test is safer and finds hidden ones.

## Sources

- [SAE J2012: Diagnostic Trouble Code Definitions](https://www.sae.org/standards/content/j2012_201812/)

## Other speed and idle control codes

- [P0500 Vehicle Speed Sensor "A"](https://diagxcar.com/codes/p0500)
- [P0505 Idle Air Control System](https://diagxcar.com/codes/p0505)
- [P0506 Idle Air Control System RPM Lower Than Expected](https://diagxcar.com/codes/p0506)
- [P0520 Engine Oil Pressure Sensor/Switch "A" Circuit](https://diagxcar.com/codes/p0520)
- [P0521 Engine Oil Pressure Sensor/Switch "A" Circuit Range/Performance](https://diagxcar.com/codes/p0521)
- [P0522 Engine Oil Pressure Sensor/Switch "A" Circuit Low](https://diagxcar.com/codes/p0522)
- [P0523 Engine Oil Pressure Sensor/Switch "A" Circuit High](https://diagxcar.com/codes/p0523)
- [P0524 Engine Oil Pressure Too Low](https://diagxcar.com/codes/p0524)
- [P0562 System Voltage Low](https://diagxcar.com/codes/p0562)
- [P0571 Brake Switch "A" Circuit](https://diagxcar.com/codes/p0571)
- [P0121 Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance](https://diagxcar.com/codes/p0121)
- [P0122 Throttle/Pedal Position Sensor/Switch "A" Circuit Low](https://diagxcar.com/codes/p0122)
- [P0123 Throttle/Pedal Position Sensor/Switch "A" Circuit High](https://diagxcar.com/codes/p0123)

## Symptoms

- [Why is my car idling rough?](https://diagxcar.com/symptoms/rough-idle)
- [Why does my car shake at idle?](https://diagxcar.com/symptoms/car-shakes-at-idle)

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Source page: https://diagxcar.com/codes/p0507
Updated: 2026-11-03
General information, not a substitute for a qualified mechanic.