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Life Hacks

This Common Mistake Could Be Why Your Check Engine Light Is Always On

There's an easy fix for this issue.


For something that’s supposed to be helpful, our car’s check engine light can be filled with a lot of mystery — and frustration. You could have just gotten a tune up not long ago and still suddenly see the little icon pop up on your dashboard. But before heading back to the mechanic (or just ignoring it), think back to the last time you fueled up: Are you sure you put the gas cap back on tight?

Why Your Check Engine Light Is Always On

Maybe you were in a hurry or got distracted, but something as simple as not twisting the gas cap back on nice and snug can be enough to flick the engine light on. The experts at Autoblog explain, “The gas cap is a part of the vehicle’s evaporative emissions system and can cause problems with the system if it has an issue. An improperly sealing fuel cap may cause an evap system leak, which will set off the check engine light when the computer detects the leak.” 

Basically, the fumes will hit the computer in our engine, which then tells the dashboard to alert us. Wouldn’t it be nice if it could also be a bit more specific about what the issue was instead of the catch-all engine indicator? But if you’re pretty sure everything else seems to be working fine, this could be a good place to look first. You shouldn’t just tighten the cap as-is, but take it off and then put it back on — twisting until you hear it click — to properly reseal the tank. 

If the engine light is still on after that, you might have a faulty cap that needs replacing. Autoblog lists signs indicating this also including the smell of fuel while inside the car or not hearing that click when you try to tighten the cap. You’ll need to get it looked at by a professional so they can run a scan of the engine’s computer for trouble codes to verify that’s the problem.  

The Bottom Line

Of course, it could be a completely different issue entirely if re-tightening the cap doesn’t do the trick, which the scan can also clear up. Reminder: If the check engine light is blinking, that’s usually a sign your car has a bigger issue that should get looked at by a professional ASAP. A non-blinking indicator, however, is more likely to be less crucial. 

Regardless of what’s going on, here’s hoping there’s an easy fix to clear the dashboard alerts and drive safe!

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