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7 Reasons Your Cadillac Check Engine Light is On

Great, the check engine light came on.

It never happens at a convenient time, does it?

Don’t put off the problem too long or it could worsen. And, whatever you do, don’t disconnect the battery leads to get the light to go away. Sweeping a problem under the rug doesn’t fix it.

The first step is to consult your vehicle service repair manual.

Secondly, consider purchasing an OBD II tool. This is the tool mechanics use to diagnose that check engine light. I bought mine for $25, and it saved me a lot of trips to the shop.

Read on for some common reasons your Cadillac check engine light may have come on.

1. Loose Gas Cap

Oddly enough, this is the most common reason for a Cadillac check engine light to show up.

It turns out the computer is very picky about the gas cap. That’s reasonable though – if a foreign contaminant gets in the tank and runs through the engine, it could spell disaster.

As you might have guessed, the fix for this particular issue is quite simple. Before you just screw it on tighter, however, inspect the gas cap carefully.

It’s possible that there is some damage that prevents a tight seal, in which case you’ll need to replace the gas cap.

2. Faulty Spark Plug or Ignition Coil

Spark plugs and ignition coils serve the same purpose: they provide the spark to ignite the fuel that brings your car to life.

While bad spark plugs are a pretty easy problem to solve, it’s also a problem that has significant consequences. Namely, your car has trouble starting.

If you notice a Cadillac check engine light after experiencing difficulty getting your engine to start, you should suspect your spark plug.

The faulty spark plug only affects your car when you start it, so you needn’t worry about the light while driving.

3. Bad Oxygen Sensor

For any combustion to take place you need both fuel and oxygen. The oxygen sensor is responsible for monitoring the amount of oxygen present in your engine. The information is used to adjust the level of oxygen to maximize the efficiency of fuel combustion.

Translated into layman’s terms, a faulty oxygen sensor can cause your car to burn fuel faster and reduce your average miles per gallon.

The good news is that oxygen sensors are fairly cheap to replace. You’re actually losing more money on gas than on replacing the sensor.

If you see that Cadillac check engine light come on, get it checked out quickly to save yourself a buck!

4. Air Intake Duct Leak

If your engine stalls, hesitates, or overheats unexpectedly, have someone stand outside near the engine when you turn the car on next.

Do you hear a strange whistling or hissing?

That noise, in combination with a Cadillac check engine light, probably means there’s a leak or crack somewhere in your air intake system.

While not an immediately harmful problem, a leak in this system should be addressed early to prevent costly problems down the road. A compromised system can allow contaminants like dust and dirt into the engine, which will eventually cause it to break down.

More immediately, a leak in your air intake prevents the vehicle from accurately measuring the airflow. This can cause problems similar to the bad oxygen sensor – poor fuel efficiency among them.

5. Engine Misfire

If it’s a serious incident, you’ll often be able to hear or feel and engine misfire before the check engine light shows up.

If you hear a loud pop or feel abnormal shaking coming from the engine, and the Cadillac check engine light comes on immediately, you probably just experienced an engine misfire.

Usually, a misfire is the result of a dying spark plug or ignition coil. The fix is simple, albeit somewhat expensive.

If you determine this is the cause, try repairing it yourself. It’s not too difficult after watching a YouTube video or two.

Another reason for engine misfires is carbon buildup on the cylinders. This is usually a result of using poorer quality gas.

In this case, the misfire is not a serious problem. The next time your tank is low, refill it with the premium gasoline option and an additive meant for cleaning cylinders.

6. Engine Coolant Temperature Sensor Failure

Your engine coolant plays a vital role in your car’s health. Not only does it prevent overheating, it also maintains temperature in a range for ideal fuel combustion.

And the sensor that monitors your engine coolant is often a culprit in Cadillac check engine light instances.

If your car overheats, you notice poor fuel economy or witness black smoke coming from your engine you should have your coolant temperature sensor inspected.

This sensor, in particular, is crucial to the continuing health of your vehicle’s engine. Operating at high temperatures places undue stress on the engine. Get it fixed as soon as possible or you’ll regret it later.

7. Catalytic Converter Failed

The catalytic converter is part of the emissions system — it helps reduce the pollutants your car emits.

And, for the most part, it is good for the whole life of your vehicle.

Occasionally, though, it fails or gets clogged. When clogged, the air is unable to escape from your exhaust and ends up going back into the engine. Among other problems, this can cause a severe drop in fuel efficiency.

Other symptoms include a failure to accelerate when you step on the gas pedal or your car refusing to start.

The number one indicator is failing an emissions inspection. Any good technician will check out your catalytic converter if you fail inspection.

Never Ignore Your Cadillac Check Engine Light

Ignoring a check engine light is a surefire way to cause serious damage to your vehicle.

Most of the time, a check engine light is a minor problem that can be fixed quickly and cheaply. The longer you wait to address it, the more likely it is to escalate into a problem that puts your vehicle in the shop for several days while it undergoes repairs.

That’s when a repair becomes costly.

If you want to save yourself a few bucks, why not try repairing it yourself? Many problems can be fixed for just the cost of the part and a couple hours of your time.

Check out this guide on Cadillac Repair Tips and get started!