Catalytic Converter Protection Function (IGN. CIR. Monitoring)

OPERATION
Malfunctions on the primary side of the ignition system are detected by the Digital Motor Electronic (DME) control unit and result in the injector valve on the relevant cylinder being switched off. This prevents an impermissible accumulation of uncombusted gasses in the catalytic converter.
In addition to monitoring the primary circuit, the system monitors the integrity of the secondary ignition circuits.
The ignition circuit monitoring function detects misfiring on a cylinder-selective basis and discontinues injection to the affected cylinder. Ignition spark output is communicated to the engine control module via a 240 ohm shunt connected to the common ground lead of the coils.