Circuit Description

The ignition control module (ICM) has independent power and ground circuits. The circuits between the ICM and the powertrain control module (PCM) consists of the following circuits:

• The ignition control (IC) timing signal
• The IC timing control
• The low resolution engine speed signal
• The low reference signal

The ICM sends 3X signals to the PCM and controls the timing advance during engine cranking. The timing advance changes to PCM control after the following actions occur:

• The PCM receives the second 3X signal.
• The PCM applies 5 volts to the IC timing signal circuit.
• The timing advance switches to PCM control.

If the PCM detects an open in the IC timing signal circuit, DTC P1352 sets.