Ignition System: Testing and Inspection

ELECTRONIC IGNITION (EI) SYSTEM DIAGNOSIS

CIRCUIT DESCRIPTION
The ignition control module (ICM) has independent power and ground circuits. The circuits between the ICM and the powertrain control module (PCM) consist of the following circuits:
- The IC timing signal circuit
- The IC timing control circuit
- The low-resolution engine speed signal circuit
- A low reference signal circuit

The ICM sends 3X signals to the PCM. The ICM controls the timing advance during engine cranking. The timing advance changes to PCM control after the following actions:
- The PCM receives the second 3X signal.
- The PCM applies 5 volts to the IC timing signal circuit.

TEST

Steps 1-2:

Steps 3-7:

Steps 8-12:

Steps 13-16: