Unlock the Mystery of Check Engine Light Codes

It happens when you’re in the middle of nowhere. Or in the middle of the city. A warning light flashes on your dashboard, urging you to CHECK ENGINE. It immediately strikes fear in the heart, a fear of the unknown. A sense of panic sets in. Your significant other is rattled, “what’s wrong with the car now,” they ask with trepidation. You feel an impulsive need to drive immediately to a dealership to find out what’s wrong. The seed has been planted: it’s a money tree and you’re about to fertilize it with your bank account.

The Check Engine Light is a great thing. It lets you know that something’s amiss with your vehicle’s engine, often before it becomes a huge issue. It’s also a fabulous way for the dealer to get you to come back to their service department.

In the old days, there was no way for average folks to find out what the codes meant without visiting a professional with an expensive code reader. Thankfully, the smartphone revolution brought check engine enlightenment to the masses.

There’s a doorway into your car’s computer system underneath the dashboard. It’s called the Onboard Diagnostics port, or OBD for short. By law every new car, truck and SUV sold in America is required to have an OBD port since the 1996 model year.

Thanks to Apple and Google, it’s now easy access the port with an iPhone or Android device and read the codes with an app … but you need to plug a dongle into the port. These dongles are relatively inexpensive and can be purchased on eBay or Amazon for less than $20.

While there may be free code reader apps, it’s best to invest in an app that’s well-supported. I like to use Dash Command on my iPhone. When a Check Engine light flickers on, I fire up the app and immediately find out what’s wrong. I can ascertain whether it’s a relatively simple repair (like replacing a mass air flow sensor) that I can tackle myself, or if I need to consult a professional mechanic for more complicated work.

If you’re looking to buy a used car, you can bring your OBDII dongle along with to identify the CEL codes when you consider the purchase. If you’re selling a used car, you can find out what’s wrong and either get it fixed, or provide the information to potential buyers. A little information can go a long way.

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