Parts for your 2012 Subaru Impreza-Fuel cap

2012 Subaru Impreza fuel cap – purpose, care, and when to replace

Yes, the 2012 Subaru Impreza uses a conventional, threaded fuel filler cap. This is confirmed by Subaru’s 2012 Impreza Owner’s Manual (fuel filler lid and cap instructions) and Subaru service documentation for the EVAP system, which even lists DTC P0457 “Loose fuel cap” as a common trigger for a Check Engine Light. So the fuel cap is very much relevant on this model.

On a 2012 Impreza, the fuel cap’s job is simple but critical: it seals the neck of the tank to stop petrol vapours escaping, keeps dust and water out, and allows the EVAP system to do its emissions work properly. A good cap helps maintain the right tank pressure, protects air quality, and prevents that whiff of fuel around the car after a fill. It also helps avoid nuisance faults that can light the dash up.

During regular servicing, it’s smart to give the cap a once-over. Check the rubber seal for cracks, flattening, or hardening, and make sure the cap tightens until it clicks. If it won’t “click” or it feels loose, it’s time to sort it. Wipe the sealing surface and the filler neck with a clean, lint-free cloth—no oily sprays or grease on the seal, as that can damage rubber and confuse the EVAP system.

Replacement is inexpensive and can save hours of diagnostic grief. Choose a genuine Subaru cap or a high-quality equivalent that’s EVAP-compatible for the GP/GJ-series Impreza. Locking caps can be handy, but only use one specifically listed for the 2012 Impreza, the wrong venting/valve design can trigger EVAP leaks or refuelling issues.

• Signs it’s time to replace: persistent fuel smell near the rear quarter, a cap that won’t click tight, a perished or cracked seal, a broken tether, or repeated EVAP codes like P0440/P0442/P0456/P0457 after refuelling.
• Good habits: open the fuel door with the cabin lever, remove and refit the cap carefully, and tighten until you hear several clicks. If the Check Engine Light appears after a fill, recheck the cap first.

As part of routine maintenance, having the cap inspected at each service interval is a low-cost, high-payoff step. For drivers clocking big kilometres or doing dusty, coastal, or off‑road trips, more frequent checks help keep the seal healthy and the EVAP system happy.

Where is the fuel door release on a 2012 Subaru Impreza?

It’s a small lever on the driver’s side floor area near the seat. Pull the lever to pop the fuel door, then unscrew the cap. After refuelling, tighten the cap until it clicks a few times before closing the door.

Why did the Check Engine Light come on after refuelling?

Most often, the cap wasn’t tightened fully or the seal is worn. The EVAP system monitors tank sealing, a loose or leaking cap can set codes like P0457. Reseat the cap until it clicks and drive a few trips—if the light stays on, have the cap and EVAP system checked.

Can a locking cap be used on this model?

Yes, but only one that’s specifically compatible with the 2012 Impreza’s EVAP system. A mismatched cap can alter venting and trigger leaks or refuelling issues. When in doubt, stick with a genuine Subaru cap or a proven equivalent.