Four Common Reasons Your Check Engine Light Is On

The check-engine light is an annoying thing that a lot of people choose to ignore. Because, hey, the car seems to be running fine, and who ever really knows what those lights are for anyway, right? It's probably just something wrong with the sensor or something, right? 


If your check-engine light is on, it means your engine isn't running as well as it could. That's the bad news. The good news is, most of the causes for an illuminated check-engine light are easy to fix. 

Loose Gas Cap

If your check-engine light has just popped on, the first thing to do is make sure the gas cap is screwed on properly. If it's loose or broken, there will be extra air in the tank, and that can mess up the fuel-air mixture reading as it heads into the engine, and that will trigger the check-engine light. 

This will take you 30 seconds and cost you $0, so you might as well check. 

Faulty O2 Censor

In your exhaust system, there are a couple of places where your vehicle's computer inserts itself and basically sniffs the fumes to check the mixture of air and fuel coming out of the engine. It does this with oxygen (O2) sensors, which are inexpensive little devices that will alert the computer if anything is off. 

And if the air-fuel mixture is off, your engine won't be running as efficiently as it could. Oxygen sensors are inexpensive and easy to replace, so there is no reason to put this off. 

Bad Spark Plugs

Spark plugs can last a long time, these days, but they will eventually wear out. What happens, generally, is that the plugs either get gunked up with combustion-chamber soot, or they simply wear out. In either case, your engine isn't getting the full explosion in each chamber. This results in a loss of power and a loss of fuel efficiency. 

Note that the same effects can be had on your spark plug wires, so keep them up to date, too. 

Bad Catalytic Converter

The catalytic converter is a device in your exhaust system that filters out pollution. It's a good thing, but like any other filter, it will eventually get clogged. 

When this happens, the exhaust cannot flow freely out of the engine, resulting in something of a traffic jam for air. An oxygen sensor will pick up on this and tell the on-board CPU about it. That's when the light comes on. 

Unfortunately, a bad catalytic converter is not an inexpensive fix. But it is a necessary one. You won't pass a Texas state inspection without a proper catalytic converter, and you also won't be able to get rid of that dreaded light. 

If you're having this problem right now, just bring your car to the service department at Finnegan Chrysler Jeep Dodge RAM. Our technicians are experts in their respective crafts, and not only will they quickly get to the bottom of the problem you're having, they'll make the repairs with genuine Chrysler, Jeep, Dodge, and RAM parts, giving you the peace of mind with knowing the job was done right. 
Categories: Service
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