Module, Transmission Control: Operation: M40MTA: Notes

WARNING: This page is about a different car, the 2015 RAM ProMaster 3500, 2015 RAM ProMaster 2500, and 2015 RAM ProMaster 1500. However, it is still accessible from the selected car via links, so may be relevant.

The Transmission Control Module (TCM) controls all electronic operations of the transmission. The TCM receives information regarding vehicle operation from both direct and indirect inputs, and selects the operational mode of the transmission. Direct inputs are hard wired to, and used specifically by the TCM. Indirect inputs are shared with the TCM via the vehicle communication bus.

Some examples of direct inputs to the TCM are:

Battery (B+) voltage
Ignition "ON" voltage
Brake Light Switch
Shift Lever Position
Pressure Switches
Transmission Temperature Sensor
Input Shaft Speed Sensor
Clutch Speed Sensor
Clutch Position Sensor

Some examples of indirect inputs to the TCM are:

Engine RPM
Accelerator Pedal Position
Engine Coolant Temperature
Engine Torque
Vehicle Speed

Based on the information received from these various inputs, the TCM determines the appropriate shift schedule and shift points, depending on the present operating conditions and driver demand. This is possible through the control of various direct and indirect outputs.

Some examples of TCM direct outputs are:

Reverse Lights

Some examples of TCM indirect outputs are:

Gear Engaged (to cluster/CCN)
AUTO Mode Selection (to cluster/CCN)

In addition to monitoring inputs and controlling outputs, the TCM has other important responsibilities and functions:

Storing and maintaining Transmission specific parameters
Storing and maintaining Clutch specific parameters
Storing and selecting appropriate Shift Schedules
System self-diagnostics
Diagnostic capabilities (with scan tool)