Primary and Secondary Circuit Tests
- Turn the ignition switch OFF , disconnect the battery, then detach the wiring harness connector from the ignition coil to be tested.
- Check for dirt, corrosion or damage on the terminals.
See Figures 1 and 2
- Use an ohmmeter to measure the resistance between the following terminals on the ignition coil, and note the resistance:
The resistance between all of these terminals should have been between 0.3-1.0 ohms. If the resistance was more or less than this value, the coil should be replaced with a new one.SECONDARY RESISTANCE
- Measure, using the ohmmeter, and note the resistance between each corresponding coil terminal and the two spark plug wire towers on the ignition coil. The coil terminals and plug wires towers are grouped as follows:
2.3L engines-right-hand coil pack
2.3L engines-left-hand coil pack
If the resistance for all of the readings was between 6,500-11,500 ohms, the ignition coils are OK. If any of the readings was less than 6,500 ohms or more than 11,500 ohms, replace the corresponding coil pack.
On 2.3L engines, if one coil pack is found to be defective, the other pack does not need to be replaced.
REMOVAL & INSTALLATION
See Figures 3, 4, 5, 6, 7, 8 and 9
The 4.0L engine utilizes one coil pack containing three separate coils. The 2.3L engine uses two coil packs containing two separate coils each.
- Disconnect the negative battery cable.
- Unplug the electrical harness connector from the ignition coil pack.
- Label and remove the spark plug wires from the ignition coil terminal towers by squeezing the locking tabs to release the coil boot retainers.