Circuit/System Description

WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

There are three dual tower ignition coils integrated with the ignition control module (ICM). The ICM contains coil driver circuits that operate the three coils. The engine control module (ECM) controls the spark event for each coil through the three individual ignition coil control circuits. When the ECM commands an ignition coil control circuit ON, electrical current will flow through the primary winding of the ignition coil, creating a magnetic field. When a spark event is requested, the ECM will command the ignition coil control circuit OFF, interrupting current flow through the primary winding. The magnetic field created by the primary winding will collapse across the secondary coil windings, producing a high voltage across the spark plug electrodes. The ECM uses information from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor for sequencing and timing of the spark events. The ICM wiring includes the following circuits:

Ignition voltage
Ground
Ignition coil 1 control
Ignition coil 2 control
Ignition coil 3 control
Low reference

The ignition coil 1 control circuit enables the spark event for cylinders 1 and 4. The ignition coil 2 control circuit enables the spark event for cylinders 2 and 5. The ignition coil 3 control circuit enables the spark event for cylinders 3 and 6. If the ECM detects that the coil control circuit has an incorrect voltage level, DTC P0351-P0353 will set.