Theory Of Operation

The Transmission Control Module (TCM) can detect rationality failures of the Input (Turbine) Speed Sensor and Output Speed Sensor signals as well as the wheel speed and engine speed signals received through the Controller Area Network (CAN).

The TCM performs three diagnostic checks that include:

• Multi sensor comparisons of up to three speed signals (input, output and wheel speed).
• Monitoring of the gradient of the input speed signal.
• Double failure monitoring to determine unique failure situations which could require unique limp-in functionality.