Can a Car Pass an Inspection with a Check Engine Light On​?

Car inspections are something that most people have had to deal with before. They help ensure that all of the cars on the road are roadworthy and not spewing out too much harmful material into our environment. For most people, this experience has become nothing more than an annoyance on their annual or biennial schedule. 

However, for most, finding that little orange engine symbol glowing on their dash just prior to an upcoming car inspection can be a stressful experience that we see on a regular basis in our own repair shop. If you’re unsure about what to do, an Arrowhead Audi repair mechanic in Peoria can help.

Check Engine Light

The check engine light is an integral component of your vehicle's On-Board Diagnostics (OBD) system. It has been programmed to notify you of any malfunction in the engine or the emission control system, as detected by the computer. Although it could be an indication of a severe problem in some cases, in other instances, it’s an indication of a very minor problem. 

Nevertheless, whether it is severe or not, its presence makes the inspection process rather complex. Many people wonder, can a car pass inspection with the engine light on?

Understanding Your Check Engine Light

The check engine light does not indicate what the problem is; it just indicates that a problem exists. When the check engine light appears, the car computer will record a "trouble code" that will indicate what the problem is. This is the reason why a check engine light inspection is so important.

More often than not, the problem is something relatively simple. The first thing to check is if the gas cap is loose or damaged. If the gas cap is not tightened properly, it will cause the fuel vapors to escape, and this will trigger the vehicle's emissions system to send you a warning. Other common sources of the problem include a faulty oxygen sensor, a malfunctioning catalytic converter, or spark plugs that have seen better days. Although these problems may not affect the performance of the vehicle, they all have a direct effect on the fuel and emissions.

Requirements of Inspection and Emissions

Most state car inspections can be broken down into two categories. The first is a safety inspection, which looks at such things as your tires, brakes, lighting, and windshield wipers to make sure that the physical vehicle is safe to drive. The second is the emissions inspection, which is where the check engine light comes in.

Today, inspections are highly dependent on the OBD system. Rather than inserting a probe into your rear exhaust pipe, inspectors simply hook your computer up to your dashboard to communicate with your computer. This test checks to ensure that all emission monitors have completed their self-checks. When the system indicates that there is an emission problem, the check engine light comes on. These steps are crucial for a car passing inspection.

The Verdict: Will It Pass?

The quick answer is almost always no. In most states where emissions tests are required, a vehicle will automatically fail an emissions test if its check engine light is on. The reason is easy to see: if it is on, it means there is a problem with your vehicle's emissions control system, or it cannot verify its status. This can prevent you from passing a car inspection.

Even if the light is on for some trivial reason which does not in any way impact its operation, the inspection computer will interpret the trouble code and give you a fail. Another thing you should remember is that you cannot erase the trouble codes by disconnecting your car's battery or scanning the codes with your code reader just before the inspection. 

When you erase the trouble codes, you erase the "readiness monitors" in the system, as well. This means that if you go to the inspection station and your readiness monitors have not had time to reset (which takes a certain drive cycle), your car will be declared "not ready" and you'll have to come back another time.

Putting You Back on the Road

If your check engine light is turned on, the first thing you should do is come in to Arrowhead Imports for a scan before you head out for your inspection. We can see what the trouble code is and get it fixed before you get your new sticker. Don’t try to ignore the light, thinking the problem will go away. It’s not going anywhere, and it’s not going to help you get your new sticker either. The key to passing your inspections and having your vehicle run well for years to come is proper maintenance!