Check Emission System Acura MDX – What Is It and How to Fix It?

Although it’s not a luxury brand, the Acura MDX model still earns a lot of approval and favorable customer feedback due to its gorgeous and unique design.

Who doesn’t want to wow everyone with their aesthetically eye-catching vehicle, right?

Nevertheless, the fact that Acura does not fall into the higher-end category means that some unexpected technical problems might affect the vehicle performance and oil pressure.

The check emission system Acura MDX issues, for instance, have given many drivers a headache. Where do they come from, and how should drivers tackle them?

Bryan’s Garage once again comes to the rescue. Keep scrolling for more verdicts and breakdowns!

The Check Emission System Acura MDX Message – What Does It Mean?

Check emission system Acura MDX

According to customer reports, two common factors behind the message “Check Emission System” on Acura are defective control emission systems (or EVAP) and loose fuel caps.

To analyze the issue further, learning what EVAP is and how to tighten your fuel cap is a must.

Ignoring the error message only leads to failed emission tests in the future. Authorities can fine you or even impound your car!

About EVAP


The evaporative fuel injection system in your car (EVAP for short) plays a crucial role in the control emission system.

EVAP recirculates and captures gas vapors from your fuel tank. After that, the engine will burn these vapors to reduce harmful emissions.

Two EVAP systems are at play: closed and open. The closed one traps vapors in charcoal canisters for later fuel burns. Meanwhile, open systems let the vapors escape the car and into the atmosphere.

How Does It Work?

You can identify three parts in its systems: charcoal canisters, purge valves/catalytic converter, and unburned fuel pump.

The engine will draw air from the surrounding atmosphere whenever the vehicle starts, which passes through purge valves into fuel tanks.

You can understand these purge valves as any typical one-way valve: they let air enter the tank, but vice versa is not possible. Such a design prevents toxic vapors from releasing from the tanks.

After the air filter passes through, your combustion chambers will pick up gas vapors (which would have been lost otherwise).

Behind purge valves, the air gets into charcoal canisters filled with carbon-activated pellets and brake fluid.

Here, all vapors are stored within the canisters via chemical adhesives – and keep staying there until the service engine runs true diagnosis tests on EVAP systems.

About The Fuel Caps

The Warning Message “Tighten Fuel Caps” – What Does It Mean?

In some cases, Acura drivers report that after the warning message “Check Emission Systems” shows up, they see another message mentioning the fuel cap via their scan tool.

Once the message “Tighten Fuel Caps” displays on the Acura, it indicates your fuel caps have not been tight enough, leading to engine problems, bad O2 sensor, and decreased fuel mixture performance.

How Should I Tighten My Acura Fuel Cap Then?

It’s hard to give you a definitive answer – since Acura has boasted tons of models and makes, meaning the procedure varies across each situation.

Nevertheless, the great news is that these models do not require intricate tools or equipment; you can tighten their caps and spark plugs with your hands! 

Consult the manuals, service protocol, or service departments for more detailed instructions.

What Will Happen If I Do Not Tighten My Acura Fuel Cap Enough?

As indicated above, if the fuel caps on your car are not tightened enough, your vehicle’s engine management will suffer all of it.

The dilemmas include rough stalling or idling – even amidst your driving.

Bad fuel economy and faulty sensor is another threat, destroying the vehicle’s lifespan and leading to vacuum leaks/excessive vacuum advance.

Some manufacturers issue official instructions regarding their vehicles’ defective gas caps.

Too bad, it seems Acura has never done the same thing, so your best bet is to avoid problems in the first place by tightening the caps carefully.

How To Fix The Check Emissions System Acura MDX

how to reset check emission system Acura MDX

1. Keep Driving As Usual For Some Time

This solution sounds ridiculously simpler than expected, but it DOES work! 

Driving your vehicle as usual (and doing nothing else) can reset your emission service system in many car models (including Acura, of course).

The trick works especially well if the check emissions light is only triggered due to slight electric malfunctions.

In some cases (particularly older Nalley Acura models like the 2007 MDX check emission system), the operation complexity in the car can lead to the error messages without further implication.

Bringing them to a service center for more in-depth treatments will only be a major waste of money, time, and energy – a disaster for busy and tight-budgeted people!

So, you see, if the error message displays in the early morning when you have to go to work, there’s no time for immediate fixes.

Simply drive the car out of your house and continue with your trip. The car will eventually reset if the malfunction is only at a low level.

2. Switch Your Car On and Off Three Times

Driving for 10 to 30 minutes should reset your malfunctioning systems easily – but it’s clear that this approach does not work 100% of the time. You might want to attempt something different to reset your emission Acura, then.

Step 1. Drive the car to a secure and empty park/location.

Step 2. Once you arrive, switch off the check engine lights and turn them on again. Repeat these steps three or four consecutive times.

That should fix your problematic Acura MDX Emissions light – but only if the defect is minor (the latter part is important!).

This method simply cuts down power to restart electrical malfunctioning components, including your dashboard warning light. Try it before turning to more complex strategies, detailed in the next parts.

3. Disconnect The Positive Cable of Your Battery

The two methods mentioned above apply mostly to slight defects. Hence, should they fail you, it’s time you move on to other, more intricate solutions: resetting everything.

So how to reset check emission system Acura MDX? Here is how:

Step 1. Switch off the car. Then remove its key.

Step 2. Open the car’s hood and identify its automobile battery. Next, disconnect the cables connected to its positive terminal via a tool (ex: wrench).

That will cut off electricity from the dashboards. Nevertheless, remember to tread cautiously to avoid essential damage to your body (such as electric shock).

Step 3. Enter the car, insert the keys, and switch the system to “ON”. It helps exhaust electrical power leftovers. Stay on your spot for three to four seconds, then get out again to reconnect the cable.

Step 4. Start the car engine. Congratulations! At this point, the warning indicator light should be gone.

Though we have warned that the methods can be complicated, these steps are actually pretty straightforward if you follow exactly as we instructed.

4. Consult Expert Mechanic for Inspection

And what if all three above recommendations cannot save your car? Chances are it is suffering from issues more severe than you would think. Your best bet is to drive to an auto expert and ask for their opinions.

Explain what you encounter to them and let them examine the vehicle for a quick fix. If there are no requirements for any replacements, the whole ordeal will cost you only some dollars.


Acura MDX Emissions light

1. Can I Keep Driving with The Acura MDX Check Emission System Light On?

Though severe conditions and cases do exist, it’s still safe to say that this error code is not too dangerous.

For people with no free time to bring the car to a third-party service for repair, it’s alright to keep driving the vehicle for a few more hundred miles.

Also, as previously mentioned, the problem is likely to resolve by itself if your car only suffers from a minor common issue or electrical problem.

2. How Much Will It Cost Me to Fix The Acura MDX Check Emission System?

As discussed above, the costs depend on individual users and their specific problems.

If there’s only a minor issue, defect, or warning sign, you will likely only spend a few dollars to have auto repair mechanics replace the malfunctioning parts.

However, much worse problems (decrease in power, flashing error light, excessive release of harmful gases, flex pipe leaks, et cetera) equates to much more costly repairs.


This article has listed all causes and solutions for the check emission system Acura MDX. It’s hard to pinpoint a fixed solution since many factors play a part here.

However, in most cases, the above guidelines are more than enough to make things work, improving your automotive experience and stability control even in severe driving conditions!

If you still have any additional questions or inquiries regarding this emission issue, contact Bryan’s service team.

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