Ignition-circuit monitoring

The current in the primary coil for the ignition coil is used to monitor the ignition circuit. When the engine is switched on, the current must stay within specific values during certain time thresholds.

The ignition diagnosis monitors the:

• Primary power circuit for the ignition coil
• Ignition wiring harness
• Secondary power circuit for the ignition coil with the spark plug

The ignition-circuit monitoring can detect the following faults:

• Short circuit at the primary end of the ignition coil
• Short circuit at the secondary end of the ignition coil
• Defective spark plug
• Break in wire to actuator
• Defective ignition output stage

The following are not detected:

• Intermittent faults such as loose contacts in the wire to the actuator
• Spark-over in high-tension circuit parallel to spark gab where a short-circuit in the coil does not develop