Your examine engine light, as soon as it turns on, is her Jeep"s method of letting you know that that is on-board diagnostic system has detected a problem. Due to the fact that the irradiate doesn"t provide you lot information, the only method of identify why the irradiate is top top is to run a straightforward diagnostic check.

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

The inspect engine light (CEL) doesn"t give you much information, but the 5 most common reasons why the light come on in many vehicles incorporate a faulty oxygen sensor, loosened or faulty gas cap, faulty catalytic converter, faulty mass airflow sensor, or failing spark plugs and/or wires. To run a diagnostic will give you more information about why the light is on. This diagnostic tool, well-known as a password reader or scan tool, can additionally turn turn off the light, yet unless you deal with and settle the underlying issue, the light will come top top again after ~ you"ve driven in between 25 and also 50 miles. Utilizing the tool is reasonably simple and also if you don"t have actually one, friend can get one at most auto parts stores.

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Figure 1. The CEL cautions you the your Jeep"s on-board diagnostic system has detected a problem.
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Method 1 – making use of an OBD scanner

Step 1 – discover the data connect connector

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

Make sure your Jeep is off prior to starting.Open driver"s side door and reach under the dashboard. The DLC is situated on the far left side, towards the front and also slightly diagonal to the steering wheel.Figure 2. Locate the DLC.Step 2 – affix the diagnostic scannerPlug the scanner into DLC and also then turn on your Jeep Cherokee.Figure 3. Affix the diagnostic scanner.Step 3 – operation the diagnostic scanTurn ~ above the scanner and go to the appropriate screen for diagnosing why your Cherokee"s CEL is on. The diagnosis might take a couple of minutes to completely run.When the diagnosis is complete, your scanner will certainly generate a list of codes certain to what"s causing the light to come on. If you"re not familiar with the codes and what they mean, your owner"s hands-on may incorporate this information. Write down the list of codes that your scanner created after perfect the diagnostic scan.Figure 4. Wait because that scanner to pull up the CEL codes.Step 4 – Reset the check engine lightLeave the scanner associated to the DLC. The scanner will ask if you desire to erase every diagnostic results and codes. Pick "YES."Put your an essential in the ignition and turn it come the "ON" position. Execute not start the engine.Press go into on the scanner when you"ve done this. The scanner will connect with her Cherokee and tell it to turn off the CEL.Start the engine. The CEL should now be off.
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Figure 5. Confirm that you desire it to reset the CEL.Figure 6. When computer has to be reset, the scanner will certainly let you recognize the code has been cleared.

Method 2 – Without making use of an OBD scanner

Step 1 – Reset your inspect engine lightDisconnect the confident (red) battery cable.Ground the positive battery cable to an unfavorable (black) battery cable for around 30 seconds.Reconnect the optimistic battery cable.Turn your crucial into the "ON" position, yet do not revolve on the engine.Turn headlights on, and also leave castle on for 10 to 20 seconds.Then revolve the headlights off.Turn your vital into the "OFF" position, and also let the car sit for around one minute.Turn your vital into the "ON" position, and also then start your engine. The CEL have to now be off.

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Pro Tip

Resetting the inspect engine light will certainly not deal with the issue that caused the CEL to which in the an initial place. If you carry out not identify and also resolve the issue, the CEL will likely come earlier on after friend drive between 30 and 50 miles.