Have you ever wondered if there is a way to know if someone cleared the check engine light on a car? In this article, we will show you how to use an OBD2 scanner to find out if the check engine light was recently reset.
First, it is important to understand how the check engine light is reset. Check engine light can be reset by clearing the codes with an OBD2 scanner or by disconnecting the battery.
Both methods clear all the Diagnostic Trouble Codes (DTCs) from the On Board Diangntoic computer at least temporarily. This procedure also reset the various systems in the car to Not Ready state. Depending on the problem the check engine light could come back right away or could take up to two weeks to turn on.
You can not pass a state emissions test by clearing the codes this way.
To find out if the check engine light was reset, you will need a cheap OBD2 code reader. A Bluetooth ELM327 OBD2 adapter in combination with a free app (Torque, Dash Command, Free OBD2 etc) can be used as well.
Make sure that the scanner that you buy is capable of displaying I/M Monitor Readiness Status. One scanner that has great reviews is on the best selling list and is capable of showing emission status is Autel AutoLink AL319 OBD II CAN Scan Tool.