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Cindy1302's avatar

How do I get my check engine light to come on again?

Asked by Cindy1302 (806points) March 13th, 2022

Months ago my check engine light started flashing. My dad recently disconnected the battery which caused the check engine light to shut off. Vocational rehabilitation offered to pay for repairs so long as i vet 3 diagnostics from 3 different establishments but I can’t do that unless the check engine light is on. My mom said to just drive it until the check engine light comes on again but wouldn’t that be dangerous seeing as there is obviously something wrong with the car since the check engine light was flashing?

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11 Answers

HP's avatar

Something wrong with the car? How about something wrong with the light? Like a burned out bulb? Before starting the engine, does the bulb illuminate along with the rest of the instrument lights?

kritiper's avatar

Turn the ignition switch to the point where all of the dash lights come on. (This is the “ENGINE RUN” position, just before you encounter spring resistance to your turning the key to engage the starter. All of the dash lights being on is a test mode for the lights to see if they are all working and not burnt out.) Make sure the “CHECK ENGINE” light comes on during this test.

If all lights come on, start the engine and see if the “CHECK ENGINE” light is on with the engine running. If not, don’t worry about it until the light comes on and STAYS on.

You don’t have to be concerned because there is nothing dangerous about the “CHECK ENGINE” light being on. It only indicates problems with the emissions system and nothing about anything that would indicate DANGER to yourself.

Blackwater_Park's avatar

“Check engine” means nothing without context. There is likely nothing serious going on with it if the light did not come back on right away. If you want to feel better about your vehicle get one of these and check the diagnostic yourself. It’s one of the best ten bucks you will ever spend.

filmfann's avatar

The check engine light will still leave a signal in your cars history.

LuckyGuy's avatar

You need to drive the car so it can perform all its self-check diagnositcs. It might take 50 miles of typical driving to do it. When the car is fully warmed up, get out on a highway for a few miles and do a few light accels, cruises and decels. That will you can

On the assembly line final dynamometer, it took us about 4 minutes to hit all the test points on a brand new vehicle. The diagnostic for catalytic converter took the longest. Since dynamometer rolls time was so expensive we were constantly trying to reduce that number by making tweaks to the test driving cycle.

LadyMarissa's avatar

@Blackwater_Park I assume that she’s referencing back to this Q Her light came on & dad wasn’t interested in fixing it. She’s found a way to get it fixed & now the light isn’t on.

I’d take mine to an auto parts store & ask them to run a check on it. My car holds the last several codes so even IF the light goes out, I can still get the info to a mechanic. I purchased one of those OBD II readers so I can see the code for myself & do a quick internet search so I know how quick I need to get it to a mechanic.

Since her dad knew how to get the light to go off, I wouldn’t worry until the light comes on again. It must not be a serious problem or the light would be back on already.

Blackwater_Park's avatar

@LadyMarissa Either way, a $10 reader and a smartphone will tell @Cindy1302 what’s going on with her vehicle. Also @Cindy1302 if it does come back on the flash pattern is a diagnostic that you can look up and will at least narrow down what the issue may be. Often it’s a sensor of some kind. If it’s not blinking then it’s usually nothing to worry about but you’ll need a reader or someone with one to tell you why it’s barking at you. Some auto parts places will read it for free but the dealer will almost certainly rip you off and charge you to read the codes.

LadyMarissa's avatar

Some auto parts places will read it for free but the dealer will almost certainly rip you off and charge you to read the codes.

That’s WHY I start with the auto parts store. I won’t even look at a dealership as I drive by for fear I’ll receive a bill from them!!! LoL

Forever_Free's avatar

A “Check Engine” light does not always mean there is a serious issue. Sometimes it does and because there are more sensors reporting could mean something that needs to be reviewed.
Yes, the battery disconnect will reset everything and may take 50–100 miles to see the light again. There is a history stored in the cars computer that can be reviewed.
Either spend a ton of money and take it to a dealer to review or drive it until the light comes on again. Then go to an Auto Parts store and have them read the code for you to get some indication of what area the issues is in.

LuckyGuy's avatar

Autozone and Advance Auto will check your codes for free.
I would still give the tech at least $10. Most will try to refuse but you should insist.

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