Transmission Control Module

PURPOSE
The Transmission Control Module (TCM) receives the following information from the PCME:
- Engine speed signal from PCME
- Throttle opening (from the throttle position potentiometer)

The information is used by the TCM to determine when a gear change is required.

To coordinate functioning and achieve smooth operation, the engine management PCME provides the electronic transmission control (TCM) with engine speed and load inputs. In return, the TCM provides a signal which causes ignition timing to be momentarily retarded on upshifts. This reduces transmission torque input, resulting in smoother shifts.