1. Diagnosis:
* Check the obvious: Start with the easiest checks. Inspect the #1 ignition coil wire and boot for any visible damage (cracks, burns, loose connection). A damaged wire or loose boot can cause intermittent or complete loss of spark. Replace the damaged component if needed.
* Inspect the Coil: Carefully examine the ignition coil itself for physical damage. Look for cracks, burns, or any signs of overheating.
* Test the Coil (Recommended): This requires a multimeter. You'll need to test both the primary and secondary resistances. Your Jeep's repair manual will have the specific resistance values for the coil; look for something in the Ohms range for the primary and Kiloohms for the secondary. A value outside the specified range indicates a faulty coil. *Important:* Disconnect the negative battery terminal before doing any electrical testing.
* Check for Power and Ground: With the ignition on (but engine off), use your multimeter to check for power at the coil's power wire and a good ground connection. A lack of power or a poor ground will also prevent the coil from functioning. Trace the wiring to ensure it's not corroded or broken.
* Check the PCM (Powertrain Control Module): In rare cases, the PCM itself might be faulty. However, it's less likely than the coil or wiring problems. A PCM issue would usually throw multiple codes.
2. Repair:
* Replace the Ignition Coil: This is the most common solution. If your testing shows a faulty coil, replace it with a new one of the correct type for your Jeep's engine. Make sure to get a high-quality replacement coil to prevent future problems.
* Repair Wiring: If you find damaged wiring, carefully repair or replace it. Solder any connections and use heat shrink tubing to insulate them.
* Address Poor Grounding: If you find a poor ground connection, clean the grounding point or replace the ground wire.
3. Tools and Parts You'll Need:
* Multimeter
* Socket set (to remove the coil)
* Replacement ignition coil (for cylinder #1)
* Wire connectors/crimps/heat shrink tubing (if wiring needs repair)
* Possibly a new spark plug wire for cylinder #1 (if damaged)
Important Considerations:
* Jeep Repair Manual: A repair manual specific to your 1996 Jeep Grand Cherokee is crucial. It will provide detailed wiring diagrams, resistance specifications, and torque specifications for the bolts.
* Safety: Always disconnect the negative battery terminal before working on any electrical components. Be careful when working around the ignition system, as high voltage is involved.
* Professional Help: If you're not comfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic. Incorrectly diagnosing or repairing this issue could lead to further damage.
The process is simpler if you have a reliable service manual, which will give you detailed diagrams and specific values for resistance checks. Failing to follow proper safety procedures can result in injury, so proceed with caution. Remember to clear the trouble code after making the repair using an OBD-II scanner.
