My father's 2014 Toyota Corolla recently had its check engine light pop on, but when he had my older brother check it out, it turned out nothing was wrong. He ignored it for about two weeks before he got concerned. He decided to bring it to the nearest auto repair shop run where a family friend works, and the same thing came up. There was nothing wrong with his car. At this point, it's been about a month, and the light is still on. What should I do?

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    Welcome to Motor Vehicle Maintenance & Repair! The light doesn't come on for "no reason". There has to be a code behind it, whether it's something which is innocuous or vehicle threatening, there's something there. Maybe the CEL is lit from a bad ground, who knows. Commented Nov 4, 2021 at 23:58
  • Agree with @Paulster2. If you took it to a mechanic and he did not put a scanner on it to check for codes I would take it to another mechanic.
    – MJH
    Commented Nov 5, 2021 at 0:14
  • Were they able to turn the lamp off? If so, when did it come back on?
    – HandyHowie
    Commented Nov 5, 2021 at 13:31
  • It's possible you have an intermittent error which throws a code, then self-corrects. Were there any codes showing at all?
    – GdD
    Commented Nov 5, 2021 at 15:11
  • Try AutoZone or other auto parts store for a free reading of error codes. When the engine symbol is on, there's at least one error code stored in memory waiting for a reader or scantool to decode it. Repair shops may be reluctant to provide info as this can affect their 'bottom line' if a customer goes elsewhere for info. You're always free to choose repair shops, dealers, independent mobile techs, auto parts stores providing free readings or friend with a reader/scantool. There are many readers and scantools to buy for primal use too.
    – F Dryer
    Commented Nov 8, 2021 at 17:10

2 Answers 2


I'd have it scanned. Even if it still runs fine, there's definitely a code there. Oddly enough, my mother owns a '97 geo tracker that the light's been on since 2000, and nothing we do can fix it. Although it's unrelated, I just thought this was an interesting point. I'd still have your toyota scanned and if there's nothing actually wrong, I'm sure there's a way to turn it off. I'm an enthusiast, not an expert, so take what I say with a grain of salt, but still, my point stands.


There was nothing wrong with his car. At this point, it's been about a month, and the light is still on.

No way can the shop claim there's nothing wrong with the car.

If the light is still on, it has caused a code. The code is visible to any OBD2 reader that can tell what's exactly at fault. Of course, some codes may indicate an issues that may be hard to troubleshoot, but the code is a good start. If you don't know what the code is, you don't know that there's nothing wrong with the car.

However, there's one very common way to cause the light to turn on. It's a loose gas cap. In this case, it's arguably the case there's nothing wrong with the car but there's something wrong with the user. Just make a habit of tightening the gas cap properly and wait for the code to disappear.

However, if it's a loose gas cap, the code should indicate that.

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