Your inspect engine light, once it transforms on, is her Jeep"s way of letting you know that the on-board diagnostic system has actually detected a problem. Since the light doesn"t provide you much information, the only method of determining why the irradiate is ~ above is to run a basic diagnostic check.

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This article uses to the Jeep cool Cherokee WJ (1999-2004).

The check engine irradiate (CEL) doesn"t give you much information, yet the five most common reasons why the light comes on in most vehicles encompass a faulty oxygen sensor, loose or faulty gas cap, faulty catalytic converter, faulty mass air flow sensor, or failing spark plugs and/or wires. To run a diagnostic will provide you more information around why the light is on. This diagnostic tool, well-known as a code reader or scan tool, can also turn off the light, yet unless you address and settle the basic issue, the light will come on again after ~ you"ve driven between 25 and also 50 miles. Using the device is reasonably simple and also if you don"t have one, you can get one at many auto components stores.

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Figure 1. The CEL advises you the your Jeep"s on-board diagnostic system has actually detected a problem.
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Method 1 – utilizing an OBD scanner

Step 1 – uncover the data connect connector

The data connect connector (DLC) allows you to affix the OBD scanner to your Jeep"s ECU.

Make sure your Jeep is off prior to starting.Open driver"s side door and also reach under the dashboard. The DLC is situated on the much left side, towards the front and slightly diagonal to the steering wheel.Figure 2. Situate the DLC.Step 2 – affix the diagnostic scannerPlug the scanner right into DLC and also then revolve on her Jeep Cherokee.Figure 3. Attach the diagnostic scanner.Step 3 – operation the diagnostic scanTurn on the scanner and go to the appropriate screen because that diagnosing why your Cherokee"s CEL is on. The diagnosis may take a couple of minutes to completely run.When the diagnosis is complete, her scanner will generate a perform of codes certain to what"s resulting in the irradiate to come on. If you"re not acquainted with the codes and also what castle mean, her owner"s manual may include this information. Compose down the perform of codes that your scanner generated after perfect the diagnostic scan.Figure 4. Wait because that scanner to traction up the CEL codes.Step 4 – Reset the examine engine lightLeave the scanner connected to the DLC. The scanner will ask if you want to erase every diagnostic results and also codes. Select "YES."Put your vital in the ignition and also turn it to the "ON" position. Execute not start the engine.Press enter on the scanner when you"ve done this. The scanner will connect with your Cherokee and also tell it to turn off the CEL.Start the engine. The CEL should now it is in off.
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Figure 5. Check that you desire it to reset the CEL.Figure 6. When computer system has to be reset, the scanner will certainly let you recognize the code has actually been cleared.

Method 2 – Without using an OBD scanner

Step 1 – Reset your check engine lightDisconnect the confident (red) battery cable.Ground the confident battery cable to an unfavorable (black) battery cable for roughly 30 seconds.Reconnect the positive battery cable.Turn your key into the "ON" position, but do not turn on the engine.Turn headlights on, and also leave them on because that 10 come 20 seconds.Then revolve the headlights off.Turn your vital into the "OFF" position, and also let the automobile sit for about one minute.Turn your an essential into the "ON" position, and then begin your engine. The CEL must now be off.

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Pro Tip

Resetting the examine engine light will not solve the problem that caused the CEL to come on in the first place. If you do not identify and also resolve the issue, the CEL will most likely come ago on after friend drive between 30 and also 50 miles.