Until now, for the diagnosis of ignition, only the primary power circuit of the ignition coil and the wiring harness were monitored. It was not possible to say anything about the events on the secondary side and the ignition sparks. There is now a system that can be used to assess also the secondary side of the ignition coil with the spark plug.
This ignition-circuit monitoring can detect the following faults:
-Short circuits and current shunts on the primary side of the ignition coil
-Short circuits and current shunts on the secondary side of the ignition coil, spark plug
-Power interruption of the control device
-Defective igniter output stages
The following cannot be detected:
-Sporadic faults, for example loose contacts in the control wire
-High-voltage spark-overs parallel to the spark plug path, without forming a coil short circuit
The evaluation of the ignition circuit takes place on the basis of the current in the primary winding of the ignition coil. The current must remain within certain values over certain time limits during switching on.