Auto Repair - Why is My Check Engine Light On?

I get the check engine light question all the time. The answer as to why it's on is that I have no idea. There are literally thousands of reasons a service engine light can illuminate. Oxygen sensors, crankshaft position sensors, loose gas caps, rodent-chewed wires - the list goes on….

One thing is certain – you should get it checked. But that is such an inconvenience! You have to schedule an appointment, drop off your car, pay a diagnostic fee, and then wait for the dreaded news, and cost.

Here’s a quick temporary solution that can ease your mind and may even reduce the strain on your wallet…. (You can also learn more @ check engine light)

Most major Auto Parts stores (Napa, AutoZone) will scan your vehicle for free. While we need to be careful not to follow the advice and diagnosis of the parts guy scanning your vehicle for check engine light codes, it may ease your mind to know just what circuit and/or component is malfunctioning.

I recently tested this free service at AutoZone when the engine light came on in my wife’s minivan. They quickly scanned my vehicle and pulled code PO135. They proceeded to print out a brief description of what this means and what component was malfunctioning. It turned out to be the heating element inside the oxygen sensor. Having seen this code many times I knew that if I installed a new oxygen sensor I’d be all set. It also wasn't an urgent repair, requiring me to stop eveything to get it fixed right away...

Auto repair shops will charge an hour’s labor to tell you this. If that’s all they’re doing, an hour is probably not justified. However, if it’s backed up with documentation, print outs, and a solid recommendation of what it will take to repair and/or proceed, then that is worth it – usually.

It’s the not knowing that drives us nuts! That’s why I suppose I’m peppered with this question weekly. So, if you must know, and don’t want to pay anything, check out a major auto parts store and see what pops up during the free scan.

Let me know how you make out…