Clear the codes in your 2003 Jeep Wrangler after repairing the issue that created the codes. Since the codes indicate what went wrong but don't necessarily point directly to the component, it's important to reset the check engine light and see if it comes back on. If it does, and shows the same code as before, you haven't addressed the trouble. For instance, a code indicating too lean a mixture of fuel and air could mean your oxygen sensor has gone bad or that your Jeep isn't getting proper fuel pressure.
Drive your car and allow the code to clear itself. The computer clears the "check engine" light after your 2003 Jeep has cranked and run without problem several times. The code is then stored for 40 runs, according to WJJeeps.com. If your Jeep has no issue during those 40 runs, the code will reset.
Remove your battery cables for a few minutes. With the engine off, disconnect the negative (black) battery cable first, then the positive (red) cable. Allow a few minutes to pass. Reconnect, beginning with the positive cable this time. Crank the engine and watch the "check engine" light. The code should be reset.
Start the engine, drive forward a short distance, then reverse. Shut the engine off. Doing this three times clears the engine codes from the dash in certain Chrysler models, as it imitates the three successful runs that automatically turns off the "check engine" light and relegates the code to the computer, where it is stored until the 40 successful runs have transpired.
Use a scan tool to clear the codes. A OBDll model will clear the codes for a 2003 Jeep. Connect the tool to the Assembly Line Diagnostic Link (ALDL), usually located under the dash. Check "Resources" for a picture of an ALDL. Turn the key on. Scan the engine for codes and select the option to reset them.
