Parts for your 2020 Subaru Impreza-Fuel cap

2020 Subaru Impreza fuel cap

Technical references confirm the 2020 Subaru Impreza uses a conventional screw-type fuel filler cap, not a capless system. The 2020 Impreza Owner’s Manual specifies tightening the cap until it clicks, Subaru service information discusses EVAP leak checks that can flag a loose cap (e.g., DTC P0457), and the genuine Subaru parts catalogue lists a dedicated Fuel Filler Cap for MY2020. So the fuel-cap is relevant, fitted, and part of the car’s evaporative emissions control system.

The fuel cap’s job is simple but important: it seals petrol vapours, maintains the right pressure and vacuum balance in the tank, and keeps dust, water and road grime out of the filler neck. A sound cap helps the EVAP system do its work, preventing fumes escaping to the atmosphere and avoiding a check engine light from small or large leak codes. It also stops splash-back, reduces odours in hot weather, and protects the filler area from grit that could wear the nozzle seal.

As part of routine servicing on a 2020 Impreza, the fuel cap deserves a quick once-over. Make sure it clicks three or more times when tightened, the tether isn’t cracked, and the rubber O-ring is soft, clean and unbroken. If the O-ring is hard, swollen or split, or the cap no longer clicks, replace it with a genuine Subaru cap to match the EVAP calibration. A worn cap can trigger warning lights, fuel smells, or fail a WOF/rego inspection. It’s an inexpensive fix that saves headaches.

During refuelling, switch the engine off, open the fuel door, and avoid topping off after the pump first clicks off—overfilling can saturate the EVAP canister and set fault codes. If a check engine light appears after refuelling, re-seat the cap, ensure proper clicks, and drive a few trips to allow the system to re-test.

• Wipe the O-ring and filler lip at each service or about every 10,000 kilometres.
• Do not lubricate the seal with petroleum products, a tiny dab of silicone grease is acceptable if the O-ring is dry.
• If a CEL appears after filling, tighten the cap and monitor, persistent EVAP codes (e.g., P0457/P0442) may indicate the cap needs replacement.
• In dusty or off‑road use, inspect the cap more often and replace sooner if wear is evident.

Does the 2020 Subaru Impreza have a capless fuel system?

No. It uses a conventional screw-type fuel filler cap that must be tightened until it clicks. Subaru’s owner and service documentation, plus the parts catalogue, all reference the cap and EVAP leak checks related to a loose or faulty cap.

How can someone tell if the fuel cap needs replacing?

Signs include a persistent fuel smell, the cap not clicking when tightened, a cracked tether, or a hardened/cracked O-ring. A check engine light with EVAP leak codes (commonly P0457 or P0442) after refuelling is another clue. If re-seating the cap doesn’t help after a few trips, replace it—ideally with a genuine Subaru cap.

How should the fuel cap be refitted correctly?

After refuelling, align the cap, turn it clockwise until it clicks at least three times, and ensure the tether isn’t pinched. Close the fuel door securely. Avoid over-tightening beyond the clicks—let the ratchet do its job to protect the seal.