General System Description

View: System Relational Diagram:

SYSTEM TYPE
Vehicle uses an electronic ignition system with computer controlled spark timing.

COMPONENTS AND OPERATION
Distributor assembly is a unit containing:
- Ignition coil
- Camshaft position sensor
- Ignition control module
- Cap and rotor

Camshaft position sensor provides the engine control module (ECM) with signals regarding crank angle at 180° intervals (SGT signal) and #1 cylinder TDC (SGC signal). Together with other inputs, ECM calculates ignition timing over the range of vehicle operating conditions.

ECM controlled ignition control module is the switch regulating current flow through coil primary circuit. Each time current flow is interrupted, high voltage is induced to fire the spark plugs. Except for the initial setting, timing is ECM controlled.

Distributor cap, rotor and high-tension leads direct high voltage from the distributor assembly to each spark plug at the appropriate time as calculated by the ECM.