How to Get Rid of the "Check Engine" Light

Updated on November 14, 2017
Wolfy profile image

Kate is a research enthusiast with a Bachelor of Science degree from Sonoma State University. Kate has a passion for the automotive field.

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You've fixed the issue that made your "check engine" light turn on, but now it won't turn off! This may not be your fault. Sometimes the computer in your vehicle will need a little help to see that the issue has been resolved. I'll go over a few techniques for resetting your check engine light.

This light displays itself when the onboard computer system recognizes an electrical or mechanical problem with your vehicle. When the problem is fixed, the engine light does not always turn off. This can be annoying, cause you to fail an emissions (smog) test, and could keep you from finding out about future problems the vehicle's computer might be trying to alert you to.

Of course, it is essential to be sure that the light isn't on because your engine really does still have a problem. Try one (or more) of the following approaches to turn the light off. If it does not go off, then your engine has a problem.

4 Ways to Turn Off the "Check Engine" Light

Method
Tools Required
1. Drive car and let light go off by itself.
None
2. Turn engine on and off three times in a row.
None
3. Disconnect and reconnet the battery.
Wrench
4. Use an OBD code reader.
Wrench and OBD reader

1. Drive Your Car and Let the Light Go Off by Itself

The first and easiest method for clearing the check engine light is driving and time. Most onboard computers will recheck whatever problem caused the check engine light to activate multiple times. Drive your car as you normally would. If the check engine light is still on after three days, your problem may not have been fixed or you may need to try some of the methods below to reset it.

2. Turn Car On and Off Three Times

Some vehicles will automatically reset the trouble codes that caused the initial error after the vehicle is turned on and off three times in succession. To do this, insert your key into the ignition, turn the vehicle on for about a second, and then off for about a second. Repeat this two more times then drive the car as normal. Check to see if the check engine light reset.

3. Disconnect and Reconnect the Battery

You will need a wrench. Prop open the hood and use the wrench to disconnect the positive power cable to the vehicle battery. Leave the battery disconnected for at least 15 minutes. Then put your key into the ignition and turn it three times to the “ON” position. This will clear the emissions data from the vehicle memory as well as the readiness flag data.

Reconnect the positive battery cable and turn the key in the vehicle ignition. Wait one minute and the check engine light error should be gone.

4. Use an OBD Code Reader

You will need a wrench and an OBD reader. These inexpensive readers analyze and clear engine codes. I have used the Kobra OBD scanner with great success many times for this task (see picture). To perform this method, plug the reader into the OBD port of your vehicle. This port is usually located on the underside of the dash area just above the foot well. On some vehicles you'll have to remove the door on your fuse box to access this port. Once you have connected the reader, press the "enter" button to turn it on. The device will scan your engine for any error codes. Once done analyzing, the reader will display any error codes it finds. Make note of the code or codes if you wish to cross check them in the code reader's manual or online.

Now you can press the "scroll" button to find the option to erase the code. Press enter while on this option to erase the fault code.

Following these techniques will allow you to rid the annoying check engine light as well as allow for new problems to be displayed properly. Whether you choose to manually reset the on board computer by resetting the battery or by using an OBD reader, you will be able to successfully fix the error. You may use these techniques to fix the check engine light error as well as any other errors in the future should they present themselves.

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    • Wolfy profile image
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      Kate Daily 11 hours ago from California

      Hi Penny,

      A loose or damaged gas cap is actually a pretty common reason that a check engine light will come on. Your car's computer probably just needed a little help after you fixed the issue. You did the right thing!

      Yes, as long as your check engine light stays off throughout the smog test, you should be fine. Take a look at my other article (below) which may be helpful to make certain your car passes smog. Good luck!

      https://hubpages.com/autos/Tricks-to-Passing-a-Smo...

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      Penny Lister 25 hours ago

      my check engine light was staying on so I replaced the gas cap, but the light was still on, so I took the ground cable loose from my battery, pressed the horn for 30 seconds, and i waited for 15 minutes to reconnect the cable to the battery. Once i did that, my check engine light is now off. I have driven the car approximately 30 miles since then and it is still off. Do you think I have fixed the problem and do you think i can now pass emmissions?

    • Wolfy profile image
      Author

      Kate Daily 5 days ago from California

      Rick,

      There could only be a few reasons why the check engine light would remain. These are in order from the most likely cause to the least likely:

      Possibility 1 - The problem that caused the computer's error code (which is making the check engine light illuminate) was not fully fixed. Even if you replaced the sensor, it may not have truly been a faulty sensor that is the issue. It may have been what that sensor is detecting (i.e. a bigger issue with the engine).

      Possibility 2 - There is an issue with the connection to the sensor. I know you checked for loose connections, but did you check the wiring from the computer to the sensor itself? Try doing this by using an ohm meter to get a reading on the resistance across just the sensor, then connect the sensor and find the same sensor wires back at the car's computer. Test the resistance between those two wires back at the car's computer. They should be just about the same resistance. If the resistance is significantly higher or lower than what the resistance was across just the sensor by itself, then you have an issue with the wiring and/or connection to the sensor.

      Possibility 3 - The car's computer is faulty, this is by far the least common. See items 1 and 2 above first.

      I hope this gives you a good starting point. If you would like, post what specific error code your car's computer is giving you (read the codes with the OBD 2 reader) and I can give you more ideas on where to look.

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      Rick dreves 5 days ago

      What if you've done all these procedures and your check engine light is still on replaced all O2 sensors map sensor check for all loose connections and a good ground but the engine light still on and still gives the same code that you just repaired

    • Wolfy profile image
      Author

      Kate Daily 2 months ago from California

      Hi Paul, I would definitely start by canceling the fault code to see if the code comes back. If it does then it may not have been the sensor itself that's the problem, rather it may be what the sensor is detecting. Here are some thoughts that may be helpful:

      1 - Check for loose or corroded electrical connections in the wiring harness near the sensor.

      2 - Are there any other electrical related issues with the car? If so they could be related (like a loose or corroded grounding wire).

      3 - Check the vacuum system (i.e. vacuum hoses and connectors) for any lose or brittle/broken parts. If you have a small vacuum hose with a crack in it, it could cause your fault. Try using a vacuum gauge for chasing down any issues with the vacuum system.

      Hopefully you find some of this useful for fixing your problem!

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      Paul Luckhurst 2 months ago

      Had no acceleration,fault code P0105 map sensor. I have replaced the Sensor,but still have acceleration problem (but not as bad) ? If i cancel fault code, will it clear, and reset engine back to normal operating mode

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      Krissy chestnut 7 months ago

      I have a 2005 Chevy Cobalt and my check engine light came on . So I hooked the scanner up to my car and it said for me to reset the check engine light. So I did and a few days later the check engine light came back on and it's still saying I need to reset the check engine light. Also the light goes off and then will come back on. PLease help!!! I'm at my wits end.

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      betty graske 8 months ago

      I have a 2001 toyota highlander and the engine light was on. I took it to my mechanic and he said he repaired the problem. Went down the road 2 miles and it came back on. Took it back to him and 3 days later he said it was done. Went down the road and the gas gauge was not working. Took it back again and he said the wire broke off. I have reason to believe he disconnected my engine check light. How do i have that checked without spending more money.

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      Levi 10 months ago

      Good day i have a mitsubishi lancer 4g92. I went to two different diagnostic. Both told me their scanner isnt picking up any problems. The car cranks but wont turn over. I changed plugs but im not getting any spark. I changed cam and crank sensor. None of this has worked. The check light is coming on as usual then it will go off as usual. Even with the engine light on im still not getting any reading. What is this problem i am facing? Help.

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      joeblevins 11 months ago

      Wow...unbelievable...after fixxing the oxygen sensor on my Ford Explorer XLS to get it to pass the emissions test the check engine light turned bk. On...couldnt believe it, so I thought i probably had to return to the shop for further examination but thanx to this website i followed the easy steps to reset it myself... And sure enough i unplugged the pos. Cable as described and follow the remaining steps before reattaching the cable bk on and to my amaze it WORKED!!!!... WooHoo!!!!!!....Thanx for the useful info to help solve the problem...2 THUMBS UP!!!!!!!!....

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      joeblevins 11 months ago

      Wow I cant believe after i got my oxgyen sensor fixed on my 2001 Ford Explorer XLS came bk on after having it fixed to pass Illinois Emission Test that this info i read on line wit u guys worked 100% plus ...I followed all steps provided and the one that eliminated the check engine light was unplug the pos. battery terminal and inserting the key before re-attaching the cable bk... I thought i would have to take it bk to the shop for further examination But dont need too...Thanx for the info. On how to reset the problem myself...2 thumbs up for this website....

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      Evans 12 months ago

      I followed the manual technique the light off momentarily and then came back on! Mine is a 2009 mazda bongo van. The irritating light is still on.

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      Stephanie 14 months ago

      I reseted my engine light but now before I foolly turn on the car it still turns on

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      BIG ED!!! 15 months ago

      Wooohooo. Left my dome light on, which killed the battery in my Subaru Forester. Turned the car on multiple times as indicated above and it reset the check engine light, hill descent and traction control lights and the car is back to normal. Thanks

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      John 16 months ago

      Thanks so much!! I found other sites that advised to disconnect the battery, but yours was the only one that advised to put the car in the "on" position 3 times before connecting the battery again. This seems to have done the trick. The light is no longer on.

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      ben thuku 16 months ago

      my prando check engine shows when the car inclines .

      what is the problem?

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      Your Name 2 years ago

      help my toyota probox,,when i drive 5okms,the engine gets really hot and all over sudden it switches off while on motion.when cool it takes off for a short distance and then showing check engine then it goes off!whats the issue?

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      felicia 2 years ago

      Help, my Honda fit 2007 is acting up! When I was driving on the highway yesterday the engine light turn on , also while accelarating the car was not speeding up to par. I went to take it to auto zone and they did a diagnostic test little machine that looks like a phone and it said that the oil pressure was low etc etc. What does that mean. I checked my motor oil and its fine. Is it expensive to fix? Please help me.

    • erorantes profile image

      Ana Maria Orantes 3 years ago from Miami Florida

      Thank you for the information Mr. Wolfy. It is true about what you are saying. I had the same problem with the light. And some one did all that work. The light is no longer on.

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