P0507 Code: Idle Control System RPM High
Quick Answer
The engine is idling faster than the ECU has commanded — typically caused by a vacuum leak or stuck-open idle bypass.
At a Glance
What this code means
P0507 means the engine idle RPM is above the ECU's target, and the ECU is unable to bring it down by reducing commanded idle airflow. This typically indicates that uncontrolled air is entering the engine — air the ECU isn't measuring or accounting for. A vacuum leak is the most common single cause.
Common causes
- Vacuum leak in the intake system (hoses, manifold gaskets, brake booster line)
- Stuck-open IAC valve allowing too much air bypass
- Leaking throttle body gasket
- Disconnected or cracked PCV hose
- Stuck throttle plate on drive-by-wire throttle body
Symptoms you might notice
- Idle RPM higher than normal (typically above 1,000 RPM at warm idle)
- Engine revs and doesn't settle quickly when decelerating
- Check engine light on
- Possible high idle cold-start that doesn't drop when warm
Can you still drive?
Yes, but a high idle can be disconcerting and may make the vehicle hard to control in traffic (car wants to creep forward in gear). Address it soon.
How serious is this code?
Moderate. High idle is often a symptom of a vacuum leak, which can also cause lean running and other codes.
Before you replace parts
Parts replacement is often not the first step. Before buying anything, it's worth checking these basics:
- Check the PCV hose first — it's under $30 and a very common cause of P0507
- Inspect brake booster vacuum line — this is a large-diameter hose and if cracked, causes a significant vacuum leak that raises idle dramatically
How to troubleshoot it
- Check the PCV hose — a cracked or disconnected PCV hose is a very common cause of high idle
- Inspect all vacuum hoses on the intake manifold for cracks or loose connections
- Spray carburetor cleaner carefully around intake manifold gaskets — a change in idle speed indicates a vacuum leak
- Check the brake booster vacuum line
- On IAC valve vehicles, clean or replace the IAC valve
Tools that may help
These are the types of tools commonly used when diagnosing this code. Having the right tool can save time and help confirm a diagnosis before spending money on parts.
- OBD-II scanner with live RPM data
- Carburetor cleaner for leak detection
- Smoke machine (optional)
Estimated repair cost range
PCV hose: $10–$40. Vacuum hose repair: $20–$100. IAC valve: $50–$200.
Costs vary significantly by vehicle, location, and whether you use OEM or aftermarket parts. These are general ranges for reference only.
When to call a mechanic
If you've completed the basic troubleshooting steps and the code keeps returning, or if you don't have access to the proper diagnostic tools, it's worth consulting a professional. A qualified technician can perform a full diagnosis and confirm the root cause before any parts are purchased. When in doubt, get a professional opinion — it can save you from an expensive misdiagnosis.
Real-world note
P0507 and P0505 often appear together on the same vehicle. P0507 (idle too high) almost always points to a vacuum leak, while P0505 (idle system malfunction) is more about the control system itself failing.
Informational purposes only. This guide is for educational reference and is not a substitute for diagnosis by a qualified technician. Repair costs, causes, and symptoms may vary by vehicle make, model, year, and condition. Always consult a licensed mechanic before performing major repairs.