by Jeffrey Caldwell
robby-T / creativecommons.org
Late-model vehicles, such as the Jeep Cherokee, use a system known as on-board diagnostics, or OBD II, to optimize the performance of the vehicle’s emissions components. When one of these components fails, it will send a signal to the engine computer, which will activate the check engine light on the dash. OBD II systems are extremely sensitive and can sometimes be activated without any actual failure in the emissions system. If this is the case with your Cherokee, cleaning the light is simple using a diagnostic code scanner.
Connect the diagnostic scanner cable to the vehicle’s diagnostic port. It will be located under the dash on the driver’s side of the vehicle.
Insert the key into the ignition and turn the key to the run position. Do not start the engine.
Wait for the code scanner to read the fault codes stored in the engine computer, then use the scanner to clear them.
- Make sure the key is in the run position with the engine off while using the scanner. If the engine is running, the scanner may not be able to read all fault codes. If you don’t own a code scanner and don’t want to buy one, many auto parts stores will read and reset engine trouble codes at little or no cost.
- Resetting the check engine light will not correct the underlying cause of the trouble code if an emissions component is not working properly. Ignoring fault codes can lead to significant damage to the vehicle.