Ranger 2WD V6-182 3.0L (1995)
Ignition Control Module: Description and Operation
DESCRIPTION AND OPERATION
The Ignition Control Module (ICM) is incorporated within the Powertrain Control Module (PCM) and performs the following functions:
1. Receives engine position and speed information from within the Crankshaft Position (CKP) sensor, and desired spark advance information
from within the PCM. The PCM uses this information to determine which ignition coil to fire, calculating the turn ON/OFF times of the
ignition coils required to achieve the correct dwell and spark advance.
2. Synthesizes a Profile Ignition Pickup (PIP) signal and an Ignition Diagnostic Monitor (IDM) signal for use within the PCM.
3. Sends information on system failures within the PCM and stores information for Diagnostic Self Tests. The IDM also provides the signal for
the tachometer.
Failure Mode Effects Management
During some Electronic Ignition (EI) system concerns, the Failure Mode Effects Management (FMEM) portion of the PCM will maintain
vehicle operation. If the PCM does not receive the Spark Output (SPOUT) from within the powertrain control module, it will automatically
turn the ignition coils ON and OFF using the CKP signal. However, this condition will result in fixed spark timing (10 degrees BTDC).
Ignition Diagnostic Monitor
The Ignition Diagnostic Monitor (IDM) is a function of the PCM.
1. The PCM sends information on system failures within the PCM, which stores the information for diagnostic self tests.
2. The IDM signal is also used to drive the vehicle instrument tachometer and/or test tachometer for diagnosis.
