Check engine light after filling up

I filled up my gas after it was alittle under half a tank . I tighten my gas cap . I started my car then out of the blue the check engine came on. I shut off car and tighten gas cap again making sure it was as tight as it could be . I started my car again and the solid check engine light stayed . Help !!! It is a 2006 Nissan sentra automatic 1.8 . About 70,000 miles

It can take three start/stop cycles for the light to go off if, in fact, you’ve fixed the problem. Get the code(s) read at an auto parts store.

Ok thank you . How do you know I fixed the problem ?

If the light goes off. (Assumes loose gas cap was the problem.)

Ok thank you insightful !!! Let’s hope that is it …

First and foremost check your oil before starting the car again. While the engine is cold, check the antifreeze to be sure you have enough. I only say this because even starting a car that is very low on oil or antifreeze could do major damage to the engine. And I doubt that you want to pay for an engine replacement into the $3000- $6000 range.
Then start the car and drive to a local parts store…Autozone, NAPA, advanced etc… Get the codes read and ask for a printout of the codes. Then come back here and let us know what codes were stored in the computer…along with the year make model and engine size…and maybe someone can help you.


You may be putting too much gas in the tank, though usually when you do this, the light comes on an hour or two after, not immediately. Its best not to fill after the handle clicks off the first time.

Checking fluids is something preventative that you can and should do immediately.

Getting the codes read is the definite next step. Don’t assume that it’s related to the fillup. Assume that the car has thrown up a red flag to warn you that something has gone wrong and try to find out what it is. Post the codes here and we’ll try to help.

I also second keith’s post. If you’re “topping off” your tank, it’s a good idea to discontinue the practice. That can hurt the EVAP system on some cars.