Parts for your 2017 Mitsubishi Asx-Fuel cap

2017 Mitsubishi ASX fuel cap: what it does and how to look after it

Yes, the 2017 Mitsubishi ASX uses a conventional, screw-type fuel cap beneath the fuel-filler door. This is confirmed in Mitsubishi’s 2017 ASX Owner’s Manual, which details opening the fuel door and tightening the fuel filler cap until it clicks, and in Mitsubishi service literature for the evaporative emissions (EVAP) system, which requires a sealed cap to maintain tank pressure integrity.

On this ASX, the fuel cap does more than just keep the petrol in and the rain out. It seals the tank so the EVAP system can capture fuel vapours, helping emissions, fuel economy, and keeping that whiff of petrol out of the garage. A poor seal can trigger a check engine light and EVAP leak codes, which is why the manual calls for tightening the cap until it clicks. If the cap or its rubber O-ring hardens, cracks, or the tether breaks, it’s time to replace it with a genuine or EVAP‑rated equivalent.

As part of routine servicing, it’s worth giving the cap a quick once-over:

• Inspect the O‑ring for cracks, flattening, or stickiness, replace the cap if the seal looks tired.
• Wipe dust and grit from the cap and filler neck with a clean, lint‑free cloth to protect the seal.
• After refuelling, tighten the cap until it clicks, if it won’t click or feels loose, replace it.

Tell‑tale signs of trouble include a petrol odour around the left rear of the car, a cap that won’t “click” tight, visible damage to the seal, or a check engine light soon after refuelling. Because the ASX’s EVAP system relies on the correct cap venting and sealing characteristics, avoid universal caps that don’t specify EVAP compatibility for the ASX/RVR/Outlander Sport platform.

Replacing the cap is straightforward: open the fuel door, unscrew the old cap, transfer or secure the tether if needed, and fit the new one. Tighten until it clicks and confirm the door shuts cleanly. If the check engine light appeared due to a loose cap, it will usually clear after a few driving cycles once the system completes its tests. For best results, follow Mitsubishi guidance noted in the 2017 Owner’s Manual and service docs—keep the seal clean, tighten until it clicks, and use a genuine-quality replacement when wear shows.

Technical sources referenced: 2017 Mitsubishi ASX Owner’s Manual (Refuelling/Fuel Filler Cap instructions), Mitsubishi Motors service information covering the EVAP system’s requirement for a sealed fuel cap.

Popular questions

Does the 2017 Mitsubishi ASX have a capless fuel filler?
No. The 2017 ASX uses a standard screw-type fuel cap under the fuel door. The system relies on a sealed cap for the EVAP emissions controls, so a proper cap is required.

Why did my check engine light come on after refuelling?
The most common cause is a loose or worn fuel cap. If the cap isn’t tightened until it clicks—or its seal is damaged—the EVAP system can detect a small leak and trigger a warning. Re-seat the cap, drive a few trips, and it often clears. If not, have the cap and EVAP system checked.

How often should the fuel cap be replaced on an ASX?
There’s no fixed interval, but it should be inspected at each service. Replace it if the O-ring is cracked or flattened, if it no longer clicks tight, or if you notice fuel odours or recurring EVAP leak codes.