There are five major reasons your check engine light comes on. One of the 5 is really cheap to fix but the other four, not so much.
Ignoring your check engine light can be extremely costly. Most repairs when caught early can cost you less than $400. Ignorance is not bliss – a major repair bill can be north of $1,500.
So, what's the cheapest reason your check engine light comes on? It's as simple as not screwing your fuel cap on correctly. (You won't have a problem with certain Fords because they eliminated fuel caps.) Unscrew it and put it back on. See if your check engine light resets itself.
Now for the bad news: the light could include a really expensive repair. Your catalytic converter when it fails is going to cost you probably more than $1,000. As outlined below, your catalytic converter is going to fail especially if you ignore your check engine lights.
Why's that? The most common reason is a failed oxygen sensor. Fixing it is a lot cheaper than a new catalytic converter (about one-fourth the cost). Where it becomes really expensive, though, is if you ignore it because it can reduce your fuel efficiency by 40 percent. Sure, gas is cheap right now but do you want to add 40 percent to your fuel bill?
Another way to get poor fuel economy is if your mass airflow sensor needs replaced. That's going to cost you about $425. Ignoring it is going to reduce your fuel economy by about 25 percent and, as we said with the oxygen sensor, why add 25 percent to your fuel bill?
Another common reason your check engine light comes on is the failure of your spark plugs or wires, which is going to set you back almost $400 (depending, of course, where you live). When these fail, without repair, your ignition coil can fail for additional expense. Ignoring both leads to the dreaded catalytic converter failure and an expense repair of $1,500.
So, how can you detect exactly what your check engine light means? The best way is getting a device that reads your onboard diagnostics. Get one that has a corresponding website that can explain the error readings in simple terms. Using the OBD readers can help you avoid having problems when you bring your car in for repair. They are great tools if your car is prone to check engine lights.
By the way, the simple repair you shouldn't do? Put a piece of electrical tape over the light. That could lead to some really expensive repairs down the road.
Images via CarCare.org.