How to Troubleshoot a 1999 Jeep Grand Cherokee

by Brooke Julia

Troubleshooting your 1999 Jeep Grand Cherokee before taking it to a service center can save you time and money. A problem may seem complicated at first but upon inspection, have a simple and inexpensive cause. Get a few basic tools and rule out causes that have easy fixes, such as a faulty battery, a blown fuse or corroded spark plug. Make sure regular maintenance has been performed, including having your transmission fluid and engine oil changed.

Shut off the engine and make a visual inspection under the hood. Check for broken or loose serpentine belts, loose wires and collapsed, broken or disconnected hoses. Look for corrosion on your battery terminals, water pump and radiator. Crank the engine and look again. Check for excessive rocking or vibration. Listen for the source of suspicious noises.

Check your fuses for breaks. Pull them out one by one to inspect them visually, or use a fuse tester for a much faster result. Fuse testers are inexpensive and reliable. Turn the car on but don't crank it. Ground your tester to a metal surface with no electricity and press the tip to each end of the fuses. If the tester lights on one end but not the other, the circuit has been broken. Replace the fuse.

Test your spark plugs for sufficient spark. Remove a wire from one of the spark plugs while the engine is running. Connect the spark plug tester to the spark plug and look for a pulse in the tester. Check each spark plug in turn. No pulse means no spark. Replace the spark plug.

Ensure your battery and alternator are putting out sufficient voltage. Turn the engine off. Touch the red (positive) tester to the red battery terminal and the black (negative) to the black battery terminal to test the battery. The volt meter should read between 12.5 and 12.8 for proper output. Repeat with the engine on to test the alternator. The volt meter should now read between 13.6 and 14.3. Lower numbers means either your battery or your alternator is struggling.

Take your Jeep to the nearest auto parts shop for a free diagnostic test of your engine's error codes. Error codes are stored within the computer and are retrieved with a SCAN tool. But first, try pulling the codes yourself by turning the key on and off in this sequence: on, off, on, off, on. Watch the "check engine" light for codes. It will flash several times to indicate the first digit of a code, pause for a moment, and flash some more for the second digit. For instance, code 55 will read: flash, flash, flash, flash, flash, pause, flash, flash, flash, flash, flash.


  • check Practice safety measures while working on an engine. Wear safety goggles and gloves. Remove loose clothing and jewelry, and tie back long hair to avoid getting it caught in moving parts.

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About the Author

Brooke Julia has been a writer since 2009. Her work has been featured in regional magazines, including "She" and "Hagerstown Magazine," as well as national magazines, including "Pregnancy & Newborn" and "Fit Pregnancy."

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