| Description and Operation The ignition system consists of the following: - ignition coil pack (12029)
- spark plug wires (12280)
- spark plugs (12405)
Ignition Coil Pack The ignition coil pack (12029) contains two separate coils. The ignition coils are triggered by the powertrain control module (PCM) in pairs (cylinder 1 and 4 and cylinders 3 and 2) sending one ignition spark to the firing cylinder and one to the corresponding cylinder on the exhaust stroke. - The majority of the ignition coil energy is used by the spark plug (12405) on the compression stroke.
- The firing voltage of one spark plug is negative with the respect to ground, while the firing voltage of the other spark plug in the cylinder pair is positive with respect to ground.
Crankshaft Position Sensor The crankshaft position (CKP) sensor (6C315) provides crankshaft position and rpm information to the powertrain control module (PCM). The crankshaft position sensor is: - A variable-reluctance type sensor.
- Activated by a 36 minus one tooth wheel.
Refer to Section 303-14 Electronic Engine Controls for removal and installation procedures. Camshaft Position Sensor The camshaft position (CMP) sensor (6B288) provides a signal to the powertrain control module (PCM) when the number one piston is on the compression stroke. Refer to Section 303-14 Electronic Engine Controls for removal and installation procedures. | 
