P0507 Subaru Outback
Idle Air Control System RPM Higher Than Expected · Powertrain Code · Medium · Repair: Easy
What is P0507?
Idle speed is higher than the ECM expects. May be caused by a vacuum leak, stuck IAC valve, or throttle body issue.
When the Subaru Outback triggers code P0507 (idle air control system rpm higher than expected), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Subaru Outback.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Subaru Outback.
Common Causes on Subaru Outback
- Vacuum leak from cracked PCV hose or intake boot
- Dirty throttle body causing idle overshoot
- Stuck-open IACV (older EJ engines)
- Intake manifold gasket leak on boxer engine
Symptoms
- Check Engine Light on
- Idle speed above 900 RPM
- Idle does not settle after warmup
- Racing idle
Notes for Subaru Outback
Boxer engines have intake manifold gaskets on both cylinder banks; a leak on either side can cause high idle.