Parts for your 2017 Subaru Xv-Fuel cap

2017 Subaru XV fuel cap: what it does and how to look after it

Based on Subaru’s 2017 XV Owner’s Manual for AU/NZ markets (fuel filler cap section) and Subaru service information for the EVAP system, the 2017 Subaru XV is fitted with a tethered, screw-type fuel filler cap and is not a capless design. The cap forms part of the sealed evaporative emissions system specified in Subaru’s workshop procedures and required by emissions regulations (e.g., ADR 79/04 and equivalent NZ standards). So yes—this model absolutely uses a conventional fuel cap, and it’s an important service item, not just a cosmetic cover.

The fuel cap on the 2017 XV seals the tank to keep petrol vapours contained, maintain the right pressure/vacuum balance for the EVAP system, and stop dirt and water getting into the tank. A healthy cap helps reduce hydrocarbon emissions and can even stabilise hot- and cold-start behaviour by keeping the system airtight. Subaru’s guidance is to tighten the cap until it clicks—those ratcheting clicks protect the seal and prevent over-tightening.

If the cap’s seal hardens or cracks, or the ratchet stops clicking, owners can see a check engine light and EVAP leak fault codes (often P0456/P0457 in Subaru diagnostic references), notice a petrol odour around the left rear quarter, or find the cap backing off. Because rubber ages with heat and ozone, a cap can be a wear item at 5–10 years. There’s no fixed interval in Subaru’s literature, but most workshops treat it as “replace on condition”. When replacing, choose an OEM or quality equivalent built for Subaru’s EVAP pressure/vacuum spec and with the correct tether and ratchet action, and stick with unleaded petrol of at least 91 RON as per market guidance.

• After every fill, tighten the cap until it clicks several times.
• Inspect the rubber seal each service—look for nicks, flattening, or cracks, replace if suspect.
• Wipe the filler neck lip clean so the seal beds properly.
• If a check engine light appears after refuelling, re-seat the cap, drive a few trips, and have codes scanned if it persists.
• A new cap is inexpensive insurance for EVAP integrity and WoF/rego peace of mind in NZ and Australia.

Popular questions

Does the 2017 Subaru XV have a capless system?

No. Technical material for the 2017 XV specifies a tethered, screw-type fuel filler cap as part of the EVAP system. It must be tightened until it clicks to ensure a proper seal.

Why did the check engine light come on after I refuelled?

The most common cause is a loose or worn fuel cap, which the EVAP diagnostics read as a small leak. Tighten the cap until it clicks a few times and drive normally, the light may clear after a few trips. If it stays on, have the system smoke-tested and consider replacing the cap.

How often should the fuel cap be replaced on a 2017 XV?

There’s no fixed interval in Subaru schedules, replace on condition. In Aussie and Kiwi climates, many caps last 5–10 years. Inspect the gasket at each service and replace the cap if the seal is cracked, the ratchet won’t click, or there’s recurring EVAP leak faults.