CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

I just braked hard for a deer and my check engine light came on

I was just driving home with my husband and my “check engine soon” light came on immediately after braking hard to avoid hitting a deer. I blew my horn to get it out of the road then continued driving. I just had it fully serviced in May (brought up to complete perfection to pass NY state inspections)and this is the first time I’ve had any lights come on. I am horrified that I will have to pay another $600 + to get that god forsaken light off again. Please advise as to what this problem could be and what it may cost. Thank you!

Actually, the check engine light is like an early warning system. It can inform you of things going wrong with your engine before they become life threatening (to the engine. Sometimes, to you.)
Let an auto parts store scan the engine computer for you. Bring the codes here for cussin’ and discussin’. “We can work it out!”.

There are two such lights. One, as hellokit explained, is a CEL (Check Engine Light) and the other is the SES (Service Engine Soon) light. Assuming the first follow hello’s recommendations. If it is the other, then you just make an appointment to get whatever kind of maintenance that is now due.

“It can inform you of things going wrong with your engine before they become life threatening (to the engine. Sometimes, to you.)”

. . . or to the environment.

Needless to say, you ought to be able to dodge deer all day and not have a Check Engine light come on. Assuming that it is a Check Engine light rather than a (kind of stupid) light telling you that periodic servicing is required, you probably ought to find out what is wrong even if you choose not to fix it until next year’s inspection.

Many chain auto parts stores will check and clear the light for free except, for some bizarre reason in California. My local Autozone has a sign in their window advertising the service. Get the exact code numbers that are read out and write them down for future reference. And get the code cleared. Given the situation, there is a reasonable chance that it will not come back.

By way of background, the code system was standardized in 1996. It is primarily oriented toward emissions related problems, but there is nothing in the rules that says that a car maker can’t turn on the Check Engine light if, for example, brake fluid is low. There are a few mandated checks that are somewhat flaky and come and go at random on some vehicles – most notably alerts for small pressure leaks in the fuel system (e.g. loose gas cap). Hopefully what you have encountered is one of those, it was triggered by your violent maneuvers, and once cleared won’t come back.

But if it is something other than that, you probably want to know about it.

Today I had to drive into town for groceries and after about 30 miles on my way home the “service engine soon” light went off! I have no idea why, I was just on my way to the mechanic that serviced it in May to have the “code” read. I wish I knew what happened what I did wrong and what I may have done right. But thank you all for your advice! I am looking into buying the device that reads those codes.