Jeep Cherokee

 Service Manual

Ignition system » Description and operation
Ignition coil-2.5L engine

DESCRIPTION

A single ignition coil is used with the 2.5L 4-cylinder engine. The coil is not oil filled. The coil windings are embedded in an epoxy compound. This provides heat and vibration resistance that allows the coil to be mounted on the engine.

OPERATION

The Powertrain Control Module (PCM) opens and closes the ignition coil ground circuit for ignition coil operation.

Battery voltage is supplied to the ignition coil positive terminal from the ASD relay. If the PCM does not see a signal from the crankshaft and camshaft sensors (indicating the ignition key is ON but the engine is not running), it will shut down the ASD circuit.

Base ignition timing is not adjustable. By controlling the coil ground circuit, the PCM is able to set the base timing and adjust the ignition timing advance. This is done to meet changing engine operating conditions.

Ignition system

Distributor-2.5L engine

Spark plugs

Spark plug cables-2.5L engine

Ignition coil-2.5L engine

Ignition coil-4.0L engine

Crankshaft position sensor

Camshaft position sensor-2.5L engine

Camshaft position sensor-4.0L engine

Ignition switch and key lock cylinder