Your Acura MDX‘s fuel cap is part of it’s emissions system. It keeps fuel vapor from escaping out of the fuel filler neck. The check fuel cap typically will appear if the fuel cap is bad, or if it has not been tightened all the way.
What Your MDX’s Gas Cap Does
The MDX’s gas cap is part of the Evaporative Emissions Control System (EVAP). The EVAP system takes fuel vapor and routes it back to the fuel system to maximize the amount of fuel that is burned by the engine. It also reduces emissions.
The gas cap needs a full seal on the tank to work. When it doesn’t have this full seal, the check gas cap light will come on.
Check Gas Cap Symptoms: Acura MDX
There really aren’t going to be any noticeable symptoms in the way that your engine runs. You may smell fuel vapor though. With a bad gas cap, the fuel vapor can escape into the air.
You may notice that the check engine light has come on as well. A loose gas cap can trigger it. Although, it certainly doesn’t have to.
There will also be a drop in fuel economy, although it should be rather negligible.
Acura MDX: Check Gas Cap Causes
Your MDX’s gas cap should “ratchet” closed with a satisfying click. If it is not clicking, it may be time for a new gas cap.
Next, you’d want to take a look at the rubber seal around the gas cap. You’re looking to make sure that it is intact, and that it isn’t dry rotted. If it does appear to be dry rotted or if it’s missing/damaged, get a new one.
Your may also want to check to see if there are any trouble codes related to the rest of the EVAP system. You can pick up a code scanner cheap, or your local parts store is almost always happy to provide a complimentary scan.
A lot of Honda owners report that their gas cap light came on during a particularly windy day, and that it went away on its own later.
Conclusion
If your MDX is messaging you to check the gas cap, go ahead and shut the engine off, tighten it up, and see if that fixes the problem. If there are no other related emissions trouble codes, then you probably need a gas cap. Good luck!