For most motorists, a check engine light coming on is a frustrating and confusing sign, because it can point to a host of malfunctions. We’re check engine light specialists: Frank’s Auto Repair uses state-of-the-art diagnostic tools and software to diagnose your vehicle’s problem as efficiently as possible, then fixes it quickly and correctly.
The most common causes of a check engine light
- Oxygen sensor. Its main function is to monitor how much fuel is burned. A faulty sensor sends incorrect data to the computer, which reduces your gas mileage. Cars have anywhere from two to four oxygen sensors, though they don’t usually all go bad at once.
- A faulty or loose gas cap. This can let fuel vapor leak out and set off the light. Make sure the gas cap is securely tightened. If you notice the light coming on right after you’ve gotten gas, this may be the problem.
- A bad catalytic converter. The catalytic converter’s job is to reduce exhaust gases. If it fails, you’ll notice a decrease in gas mileage, or you may lose power when accelerating. It should be replaced as soon as possible.
- Mass air flow sensor. This sensor tells the car’s computer how much fuel to add based on the air coming in through the engine. A faulty sensor can cause the car to stall and decrease gas mileage. Changing your air filter regularly, at least once a year, helps keep it from failing.
- Spark plugs and wires. Bad plugs can cause misfires, and you may feel a jolt in acceleration when that happens. They can be replaced as part of your scheduled maintenance to prevent failure.
- Dirty fuel injectors. A dirty fuel injector can cause misfiring, hard starting, stalling, hesitation and a check engine light. If you notice any of these symptoms, the fuel injectors may be the problem.
An active check engine light is also one of the most common reasons cars fail NJ state inspection, so it has to be resolved before your inspection. More on that is on our NJ inspections and emissions repair page.
Oil light: do not ignore it
This light means your engine has dangerously low oil pressure (it may be leaking or burning oil), or the oil pressure sending unit that triggers the warning light has failed. Do not keep driving. Let the engine sit and check the oil level, add oil if it’s low, and have the car checked immediately.
Temperature light
When this light comes on, your engine is overheating. Do not keep driving: if you continue, you can cause serious engine damage. It means there’s a problem with your car’s cooling system, which we cover on our air conditioning and heating page.
Other warning lights
The ABS and brake warning lights are explained on our brakes page, and the tire pressure (TPMS) light on our tires page.
Why we diagnose before we replace parts
Today’s vehicles contain dozens of sensors and electronic control systems that work together, and replacing random parts rarely solves the problem. A diagnostic trouble code gives a technician an important starting point, but the code itself doesn’t necessarily identify which part should be replaced. We use advanced scan tools to read manufacturer-specific codes, analyze live engine data and perform system tests, so we find the root cause instead of guessing. You can read more in our post on emissions repair in New Jersey.
If a warning light is on, request an appointment and we’ll help identify what your car’s computer is detecting.