Ignition Coil Pack(s)

TESTING

Primary and Secondary Circuit Tests

1. Turn the ignition switch OFF, disconnect the battery, then detach the wiring harness connector from the ignition coil to be tested.
2. Check for dirt, corrosion or damage on the terminals.

PRIMARY RESISTANCE

1. Use an ohmmeter to measure the resistance between the following terminals on the ignition coil, and note the resistance:

   Except 2.3L/2.5L engine

   • B+ to Coil 1
   • B+ to Coil 2
   • B+ to Coil 3

   2.3L/2.5L engine

   • B+ to Coil 1
   • B+ to Coil 2

   or,

2. B+ to Coil 3
3. B+ to Coil 4

   Fig. 1: Engine ignition coil harness connections — 3.0L and 4.0L engines

   Fig. 2: Engine ignition coil harness connections — 2.3L and 2.5L engines

   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

1. 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:

   Except 2.3L/2.5L engines:

   • Terminal 3 (coil 1) — spark plugs 1 and 5
   • Terminal 2 (coil 3) — spark plugs 2 and 6
   • Terminal 1 (coil 2) — spark plugs 3 and 4

   2.3L/2.5L engines (right-hand coil pack):

   • Terminal 1 (coil 2) — spark plugs 2 and 3
   • Terminal 3 (coil 1) — spark plugs 1 and 4

   2.3L/2.5L engines (left-hand coil pack):

   • Terminal 1 (coil 4) — spark plugs 2 and 3
   • Terminal 3 (coil 3) — spark plugs 1 and 4

   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.

   NOTE: On 2.3L/2.5L engines, if one coil pack is found to be defective, the other pack does not need to be replaced.