Escort L4-110 1.8L DOHC (1994)
Control Module: Description and Operation
NOTE: The Transaxle Control Module (TCM) is integrated with the Powertrain Control Module (PCM).
DESCRIPTION
Several sensors and switches allow the 4EAT system to constantly monitor driving conditions. Signals from these sensors and switches
representing vehicle speed and engine load are sent to the PCM where the information is utilized to control the transaxle shift pattern, gear
position, and torque converter lockup timing. The PCM has built-in self-diagnosis, fail-safe, and diagnostic trouble code display functions for the
main input sensors and solenoid valves.
Self-Diagnosis Function
The PCM has internal self-diagnosis functions to warn the driver if a malfunction occurs in any of the main input sensors or output
solenoids. If a malfunction occurs, the Malfunction Indicator Lamp (MIL) (CHECK ENGINE lamp) flashes.
Fail-Safe Function
When the self-diagnosis function detects a malfunction, the PCM will maintain minimum driveability through the fail-safe system by
substituting the signal from a component that is operating correctly for the signal from the failed component. The fail-safe function will
then continue a normal lockup and shift pattern to maintain minimum driveability.
