P0507 on a 2012 Subaru Forester
Idle Higher Than Expected
P0507 on a 2012 Subaru Forester indicates idle higher than expected. It usually stays drivable short-term but should be diagnosed promptly. The most common cause is vacuum leak (intake gasket, pcv hose, brake-booster hose, throttle-body gasket) (typically $80–$600). Confirm the root cause before replacing parts.
What does P0507 mean on a 2012 Subaru Forester?
P0507 is set when the ECM commands the throttle to a specific idle RPM and measures actual idle higher than that target by more than a calibrated amount (typically 200+ RPM higher). The cause is almost always unmetered air entering the engine — a vacuum leak somewhere — or a stuck throttle body / idle control issue.
This guide covers P0507 across the 2010-2014 Subaru Forester generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2010 through 2014.
Is it safe to drive a 2012 Subaru Forester with P0507?
In most cases a 2012 Subaru Forester stays drivable for short trips with P0507 active, but diagnose and repair it promptly. This is a moderate-severity code — ignoring it can lead to further damage or a failed emissions test.
What are the symptoms of P0507 on a 2012 Subaru Forester?
- Check Engine Light is illuminated
- Engine idles noticeably high (1000-1500 RPM instead of 700-900)
- Possible whistling or hissing sound from the intake area
- Reduced fuel economy
- Hesitation as the engine tries to slow when stopping
- May be paired with P0171 (lean code)
What causes P0507 on a 2012 Subaru Forester?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Vacuum leak (intake gasket, PCV hose, brake-booster hose, throttle-body gasket) Most P0507 codes trace to unmetered air entering the engine. | Most common | $80–$600 |
| Carbon-coked throttle body keeping the blade slightly open | Common | $20–$200 |
| Failed or sticking idle air control (IAC) valve on older non-ETC vehicles | Common | $80–$300 |
| Failed throttle body needing replacement and relearn | Occasional | $250–$800 |
| Sticking accelerator pedal or throttle cable (older vehicles) | Occasional | $50–$250 |
| Cracked plastic intake manifold | Occasional | $250–$900 |
| EVAP purge valve stuck open (often sets P0496 alongside) | Occasional | $80–$300 |
How to diagnose this on a 2012 Subaru Forester
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Confirm the actual idle RPM and check fuel trims
Scan-tool live data should show actual idle RPM and the target. Look at Bank 1 LTFT: a high positive number (e.g. +15 % or more) confirms a real vacuum leak. Trims near zero with high idle point at a throttle body or EVAP issue rather than a leak.
Tools: Scan tool with live PIDs
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Smoke-test the intake
Pressurize the intake with smoke through a snorkel cap or the throttle body. Watch every gasket, hose, vacuum tee, the brake booster line, the PCV system, and the EVAP purge line. Smoke escaping anywhere is the leak.
Tools: EVAP / intake smoke machine, Flashlight and inspection mirror
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Inspect and clean the throttle body
Coked carbon at the throttle bore prevents the blade from closing fully — the engine pulls air around the blade that the ECM cannot fully control. Clean with throttle-body-safe cleaner (never carb cleaner) and a soft brush. Perform an idle relearn after.
Tools: Throttle body cleaner, Soft brush, Service manual for the relearn procedure
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Test the IAC valve (non-ETC vehicles)
On older vehicles with a separate IAC valve, command the valve with a scan tool and watch for idle changes. A valve that does not respond, or that idles correctly with the connector unplugged, is stuck or failed.
Tools: Scan tool with IAC command
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Verify the EVAP purge valve is not stuck open
A stuck-open purge valve introduces unmetered fuel vapor at idle, causing high idle and lean trims similar to a vacuum leak. With the engine idling, disconnect the purge valve — if idle smooths out, the purge valve is the cause.
Tools: Hose disconnect tools
NHTSA complaints & recalls for the 2012 Subaru Forester
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2012 Subaru Forester. Use these to gauge how common a problem is on your specific vehicle before you start chasing Subaru Forester diagnostics.
- ENGINE 27
- VEHICLE SPEED CONTROL 18
- AIR BAGS 20
- SERVICE BRAKES 15
- ELECTRICAL SYSTEM 10
15 active recalls
- AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE Jan 2019
Subaru of America, Inc. (Subaru) is recalling certain 2010-2014 Tribeca, WRX, Outback, and Legacy vehicles, 2010-2011 Impreza vehicles and 2010-2013 Forester vehicles sold, or ever registered, in the states of Arizona, Arkansas, Delaware, District of Columbia, Illinois, Indiana,…
NHTSA campaign 19V008000 - AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE Jan 2019
Subaru of America, Inc. (Subaru) is recalling certain 2010-2013 Forester, 2010-2014 Tribeca, WRX, Outback, Legacy, and 2010-2011 Impreza vehicles sold, or ever registered, in the states of Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texa…
NHTSA campaign 19V007000 - AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE Jan 2019
Subaru of America, Inc. (Subaru) is recalling certain 2010-2014 Tribeca, WRX, Legacy and Outback vehicles, 2010-2011 Impreza vehicles and 2010-2013 Forester vehicles sold, or ever registered, in the states of Alaska, Colorado, Connecticut, Idaho, Iowa, Maine, Massachusetts, Michi…
NHTSA campaign 19V009000 - ELECTRICAL SYSTEM:IGNITION:SWITCH Apr 2019
Subaru of America, Inc. (Subaru) is recalling certain 2009-2013 Forester vehicles, 2008-2011 Impreza vehicles, 2008-2014 WRX vehicles, 2005-2014 Legacy vehicles, 2005-2014 Outback vehicles and 2006-2008 Tribeca vehicles equipped with a mechanical key ignition switch installed as…
NHTSA campaign 19V297000
How do I fix P0507 on a 2012 Subaru Forester?
- Repair vacuum leak(s) found by smoke test
- Clean the throttle body and perform idle relearn
- Replace the IAC valve (older vehicles)
- Replace the EVAP purge valve
- Replace cracked plastic intake manifold (model-specific)
About the 2010-2014 Subaru Forester
The 2010-2014 Subaru Forester was commonly sold with the following powertrains: 2.5L H4, 2.0L Turbo H4. Common trims include Base, Premium, Sport, Limited, Touring, Wilderness.
The vacuum leak almost certainly is the cause
P0507 paired with P0171 (or P0174) is virtually always a vacuum leak. The high idle and the lean fuel trim both result from the same underlying problem: unmetered air entering the engine downstream of the MAF. The ECM cannot identify exactly which leak path is responsible, only that one exists. Smoke testing is the fastest path to the source.
Common P0507 leak locations by engine
- Ford 4.6 / 5.4 modular V8 — cracked plastic intake manifold, PCV hose at the rear of the engine
- GM 3.6 LFX / LLT V6 — intake manifold gaskets, PCV system
- Toyota 2GR-FE V6 — throttle-body gasket, intake plenum bolts
- Honda K-series — IACV gasket, vacuum tee at the brake booster
- Chrysler 3.5 / 3.6 Pentastar — PCV tube, intake gasket
- Most vehicles 10+ years old — hardened brake-booster hose
Idle relearn after throttle body cleaning
Modern vehicles with electronic throttle control require an idle relearn after any throttle body removal, cleaning, or replacement. The procedure varies — generally:
- Battery disconnect 30+ seconds, reconnect
- Key on, engine off, 30 seconds
- Start engine, idle 5 minutes with no load (AC off, no electrical accessories)
- Drive a short cycle including a few full stops
Some vehicles require a bidirectional scan tool to perform the relearn. Without a successful relearn, P0507 will set again within a few drive cycles even though the throttle body is mechanically perfect.
P0507 on a 2012 Subaru Forester: frequently asked questions
What does diagnostic trouble code P0507 mean on a 2012 Subaru Forester?
P0507 is set when the ECM commands the throttle to a specific idle RPM and measures actual idle higher than that target by more than a calibrated amount (typically 200+ RPM higher). The cause is almost always unmetered air entering the engine — a vacuum leak somewhere — or a stuck throttle body / idle control issue.
What are the symptoms of P0507 on a 2012 Subaru Forester?
Check Engine Light is illuminated. Engine idles noticeably high (1000-1500 RPM instead of 700-900). Possible whistling or hissing sound from the intake area. Reduced fuel economy. Hesitation as the engine tries to slow when stopping. May be paired with P0171 (lean code)
What causes P0507 on a 2012 Subaru Forester?
Vacuum leak (intake gasket, PCV hose, brake-booster hose, throttle-body gasket) (most-common). Carbon-coked throttle body keeping the blade slightly open (common). Failed or sticking idle air control (IAC) valve on older non-ETC vehicles (common). Failed throttle body needing replacement and relearn (occasional). Sticking accelerator pedal or throttle cable (older vehicles) (occasional). Cracked plastic intake manifold (occasional). EVAP purge valve stuck open (often sets P0496 alongside) (occasional)
Is it safe to drive a 2012 Subaru Forester with P0507?
In most cases a 2012 Subaru Forester stays drivable for short trips with P0507 active, but it should be diagnosed and repaired promptly — this is a moderate-severity code. Ignoring it can lead to further damage or a failed emissions test.