Check Engine Light Service Specialists

Is your check engine light on?

Let our experienced mechanics handle it—schedule Your Check Engine Light Service Here.

Family-owned and operated since 1988, C&J Automotive provides you and your family with quality auto repair services, like check engine light service, at fair prices.

Our full-service facilities in Berwyn and Newtown Square, PA are open and ready to service all makes and models including foreign and domestic, hybrid and electric cars, trucks and SUVs!

Fill out our quick form to schedule service with one of our six C&J Automotive locations today and get a free check engine light code scan!

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What The Check Engine Light Means

The check engine light is a signal from your car’s engine computer that something is wrong with the engine. To diagnose what is wrong exactly, you will need to use an OBD-II reader to get the specific diagnostic code and then research the code’s meaning. Or, you can let our certified technicians diagnose your check engine light codes, resolve the required maintenance or repair issues, and get you and your car back on the road safely!

You don’t need to freak out when your check engine light is on. But it’s important to address the problem(s) indicated by the light promptly. Ignoring them could lead to larger, costlier problems later. If your check engine light is flashing, instead of continuously and steadily on, we severely recommend bringing your car in as soon as possible!

While your check engine light may be on for many different reasons, here are the 5 most common causes of a check engine light in the northeast and their estimated repair costs as published by CarMD, an automotive telematics company, in their 2020 Vehicle Health Index.

The 5 most common causes of a check engine light

The following list of the ten most common check engine vehicle repairs in the Northeastern U.S. are based on 2,159,192 repairs in 2019 in CT, MA, ME, NH, NJ, NY, PA, RI and VT. This data applies to roughly 85% of cars, light trucks, minivans and SUVs on the road in the U.S. – foreign and domestic. Source: Corp. The average repair costs listed below are for educational purposes only and not actual C&J Automotive estimates.


Oxygen Sensors

The oxygen sensor, or O2S, measures the amount of unburnt oxygen in your car’s exhaust system. This data helps regulate the mixture of air and fuel that enters the engine's cylinders in order to maximize your car's performance.

If your oxygen sensor is malfunctioning, your check engine light will turn on. While you should get your car checked out as soon as possible, especially if you drive an older car, your engine will keep running even if the O2S needs to be replaced. However, your car will run either rich (less oxygen, more fuel) or lean mixtures (more oxygen, less fuel). Both of which are bad for your car and the environment.

If one or more of your oxygen sensors is faulty during an emissions inspection for your car, you will most likely not pass the inspection. In the long run, a bad O2S can damage components like the spark plugs and the catalytic converter.

Total Average Repair Cost in the NE (Parts & Labor): $263.64


Catalytic Converters

The catalytic converter in your vehicle’s exhaust system turns the carbon monoxide generated during the combustion process into carbon dioxide. Over time it can become clogged from leaking engine coolant, overheated or physically damaged, which restricts exhaust gasses from passing through properly.

Its failure can often be prevented by performing regular maintenance such as oil changes. If you mostly drive short distances, take your car on the highway every now and then to prevent clogging. Some symptoms of a faulty catalytic converter are: reduced acceleration, dark exhaust smoke, and the smell of rotten eggs coming from the exhaust.

Your check engine light may come on to indicate catalytic converter damage or to alert you to a clogged air or fuel filter. Don't wait to change that filter! Doing so could lead prematurely to a total catalytic converter replacement.

Total Average Repair Cost in the NE (Parts & Labor): $1,342.41


Loose Fuel Cap

Yes, a loose fuel cap is one of the most common reasons why the check engine light turns on! It seems so simple, but the cap is a crucial part of a car’s fuel delivery system.

In addition to keeping dirt and debris out of your gas tank, the fuel cap prevents gasoline fumes from leaving the tank, and helps keep the whole system under the correct pressure.

If your check engine light turns on immediately after a fill-up, pull over and make sure the cap isn’t loose. Overtime, the cap will wear down and may need replacement. And though a bad or failing fuel cap will not cause major performance issues, it can trigger the check engine light.

Total Average Repair Cost in the NE (Parts & Labor): $23.56


Ignition Coils & Spark Plugs

Your ignition coils and spark plugs are small but vital parts of your gasoline-powered vehicle’s ignition system. The ignition coils take the low, 12-volt current from your car battery and convert it into a much higher, 15,000+ voltage for the spark plugs. The spark plugs ignite the air and fuel mixture in your engine to power the combustion your car needs to run.

Overtime, these parts may corrode or simply wear down and not perform their best. If either part is malfunctioning, your check engine light will most certainly be triggered. Worn or faulty ignition coils and spark plus can cause issues like engine misfire, hesitation under heavy acceleration, and even so far ar to cause the engine to shut off unexpectedly.

Total Average Repair Cost in the NE (Parts & Labor): $381.96


Mass Air Flow (MAF) Sensor

The mass airflow (MAF) sensor monitors how much air enters the engine. This data helps your car's primary computer determine how much fuel to give to the engine—more air requires more fuel.

Your check engine light may be on because no accurate signal is coming from the MAF sensor. Without it, your car won’t know how much fuel to give the engine. This could cause the engine to run rich or lean and ultimately cause the engine to run rough and misfire. A bad MAF may also reduce your vehicles acceleration, and lead to an increase in fuel economy.

In some cases, the MAF may just need to be cleaned. In other cases it may need to be replaced. Although you may technically be able to drive with a bad MAF sensor, you should address the issue as soon as possible to prevent premature damage to other parts of your vehicle like the catalytic converter.

Total Average Repair Cost in the NE (Parts & Labor): $349.04