P0507 Code: Idle Air Control System RPM Higher Than Expected
The engine idles faster than the computer's target – most often extra air is sneaking in through a leak.
At a glance
Severity: Low
- Meaning
- Idle Air Control System RPM Higher Than Expected
- System
- Speed & Idle Control · Powertrain
- Safe to drive?
- Yes, short term
- Typical repair cost
- $0–$800
- DIY difficulty
- Easy
At idle the ECM compares actual engine speed with its desired idle rpm and trims the idle air control valve or electronic throttle to close the gap. P0507 sets when actual idle stays above the target by more than a set margin – often in the 100–200 rpm range, depending on the manufacturer – even though the ECM has already closed its idle air down as far as it can. That almost always means air is entering the engine that the ECM doesn't control: a vacuum leak, a stuck-open IAC valve or purge valve, or a throttle that doesn't fully close. A missed idle relearn after a battery disconnect or throttle body cleaning is another frequent and easy trigger.
Can I keep driving? Safe to drive in the short term. In Drive the car will creep harder at stops, so keep a firm foot on the brake, and find the leak before it causes lean running or rough idle.
Try this first – 5-minute fix
- Let the idle relearn If the battery was recently disconnected or the throttle body cleaned, start the engine with A/C, lights and blower off and let it idle until fully warm and the cooling fan cycles, then drive normally. Many engines bring idle back down on their own this way.
- Check the obvious hoses With the engine idling, listen around the intake for a hiss and inspect the PCV hose, brake booster hose and intake boot for cracks or loose clamps. Reconnecting a popped-off hose often cures P0507 instantly.
- Make sure the throttle can close Check that the floor mat or a pedal cover isn't holding the accelerator down, and on cable throttles that the cable isn't binding or adjusted too tight. Then clear the code and watch idle for a couple of drives.
How to read P0507
- P Powertrain
- 0 Generic (SAE)
- 5 Speed, idle & inputs
- 07 Specific fault
Symptoms
- Warm idle clearly higher than normal, e.g. 1,100 rpm instead of about 700
- Car pulls forward hard at stoplights in Drive
- Idle surges, sometimes with a hissing sound from the engine bay
- Clunky engagement when shifting into Drive or Reverse
- Slightly worse fuel economy in city driving
- Check engine light on, sometimes together with P0171/P0174
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Vacuum leak – cracked or disconnected hose, brake booster hose or intake gasket
- Idle not relearned after a battery disconnect or throttle body cleaning
- IAC valve stuck open or leaking IAC gasket
- EVAP purge valve stuck open, feeding vapor and air into the intake
- Throttle not closing fully – binding cable, sticky plate or tampered stop screw
- Throttle position sensor misreading or ECM software issue
- PCV valve stuck open or torn PCV diaphragm in the valve cover
Diagnosis step by step
Confirm with live data
Warm the engine fully and compare desired vs actual idle rpm, IAC counts or throttle opening, and fuel trims. Actual rpm staying high while the ECM has already pulled idle control to its minimum confirms uncontrolled air.
Tools: OBD-II scanner
Smoke-test the intake
A smoke tester reveals leaks at the intake gasket, PCV plumbing, brake booster and throttle body gasket. Positive fuel trims of more than about +10% at idle that shrink at 2,500 rpm are a classic vacuum-leak pattern.
Tools: Smoke machine, Flashlight
Pinch-test the purge line
With the engine idling, clamp or cap the purge line where it enters the intake. If idle drops back to normal, the purge valve is leaking through and should be replaced.
Tools: Pliers, OBD-II scanner
Check the PCV system and throttle stop
A PCV valve that no longer rattles or a torn diaphragm in an integrated valve cover can leak air. Also confirm the throttle plate closes completely and nobody has turned the idle stop screw.
Tools: Flashlight, Screwdriver
Clean, reseal and relearn
Clean the throttle body and IAC valve, replace a leaking IAC or throttle body gasket, then run the manufacturer's idle relearn. Clear the code and verify idle stays in spec over several drive cycles.
Tools: Soft brush, OBD-II scanner
Where the parts are
- 1Gas cap
- 2Charcoal canister
- 3Purge valve
- 4Vent valve
- 5Fuel pump
- 6Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Idle relearn (DIY or shop) | Yes | $0–$120 |
| Replace vacuum hose or PCV valve | Yes | $20–$200 |
| Replace EVAP purge valve | No | $120–$300 |
| Replace IAC valve or throttle body gasket | No | $150–$400 |
| Replace intake manifold gasket | No | $300–$800 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Field data
| Ford | 3 | Focus Bev | |
|---|---|---|---|
| Nissan | 3 | Rogue Sport, Altima |
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Will fail
With the check engine light on, the vehicle fails an OBD smog check. In areas that still sniff tailpipe emissions on older cars, a high idle combined with a vacuum leak can also push HC readings up.
Frequently asked questions
Why did P0507 appear right after I replaced my battery?
The ECM lost its learned idle values and may overshoot the target until it relearns. A warm idle with all loads off, or a scan-tool relearn on some models, usually settles it. If the code comes back, look for a leak.
What should my idle rpm be?
Most warm gasoline engines idle somewhere around 600–800 rpm in Park, a little higher with the A/C on or right after a cold start. Your scan tool's desired-idle value is the best reference for your specific engine.
Can one leak cause P0507 and P0171 at the same time?
Yes. Air entering after the mass airflow sensor raises idle speed and also makes the mixture lean, so the ECM may store both. Fixing the leak normally clears both codes.
Will a high idle damage anything?
Not quickly, but it wears the brakes and transmission engagement harder and wastes fuel. The underlying leak can also cause lean misfires over time, so don't ignore it.