Knock detection

CDM analyses the ionization signals from pin 4 on the respective ignition coils.

Fig 1: Identifying Knock Detection

Courtesy of SAAB-SCANIA OF AMERICA, INC.

• Cylinder 1 ignition coil is connected to CDM pin 16.
• Cylinder 2 ignition coil is connected to CDM pin 7.
• Cylinder 3 ignition coil is connected to CDM pin 8.
• Cylinder 4 ignition coil is connected to CDM pin 15.

CDM synchronizes the ionization current measurement with the firing order and generates a knock signal that is sent to ECM pin 37(B).