Why did your check engine light come on?
What exactly is the check engine light?
A car’s check engine light is part of its onboard diagnostics system. The engine’s computer control regulates things like ignition timing, fuel mixture, and engine speed.
When there is an issue with the motor or its diagnostic systems, the dashboard will show a warning light. The most serious warning light is the check engine light.
What does it mean?
A check engine light means that there is an issue onboard with the electronic-control system that it cannot fix.
“When the check engine light comes on it means that the car requires service as soon as possible.”
What should you do?
What you should do depends on what exactly the light is doing. If the light is solid, the matter does need to be addressed but does not require an immediate stop and tow to the closest automotive professional. If the check engine light is blinking, it’s an urgent engine issue and should be checked ASAP!
If you have the know-how or tools, you can check the code yourself. This way you can figure out the urgency level related to the required repair.
What to check
OBD scanner: If you have an OBD scanner, you can check the related check engine code. Once you have the code you can check online and see whether the issue requires immediate attention and whether it’s something you can take care of yourself.
“There are codes that correspond with the check engine light errors. You can check these yourself.”
If you can’t get the car in immediately try the following quick checks:
- Check for any serious problems requiring an immediate fix. This might be the engine overheating, the oil running low. Low oil or an overheating engine requires an immediate stop.
- Slow down and reduce speed. Take stress off the engine. Take things slowly, and if you’re towing something, stop as soon as possible.
- Try tightening your gas gap.
If none of the quick fixes resolve the check engine light problem, schedule an appointment to take your car in as soon as possible.
Check engine light codes
It is possible to check the reason why the check engine light went off. How this can be done depends on the year of your vehicle.
If you have an older vehicle made before 1996, you can check the check engine code with just your key and the car itself.
Cars newer than 1996 will require a computer scan. The good news is that you can buy a code scanner for less than $100. You can read the instructions that come with the code scanner to figure out why the check engine light has come on.
“The check engine light coming on means that there is an issue with the vehicle that the onboard computer cannot fix.”
Resetting the check engine light
There are 4 ways to reset the check engine light.
- Drive the car and wait for it to turn off. If the problem has been corrected, most computers will clear the error code on its own after so many miles.
- Turn the car on and off three times. The ECU will reset the warning code after the car is turned off and on rapidly three times.
- Disconnect the battery. To clear the emissions and other sensory data triggering the check engine light, disconnect the battery and leave disconnected for 15 minutes. Then switch the key three times between the “ignition” and “on” position. Reconnect the battery and turn the car back on. In a minute or two, the check engine light should clear.
- Scan the computer with an OBD Code Reader. These readers can be purchased online and in stores for less than $100.
A deeper dive — Related reading from the 101:
Doing these DIY car maintenance repairs can keep your check engine light from coming on.
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