Theory Of Operation

The Transmission Control Module (TCM) monitors the system voltage level at the TCM supply voltage terminal for the following failure conditions:

• System Voltage Excessively Low
• System Voltage Low
• System Voltage High

If the TCM supply voltage is below a threshold that is lower than the System Voltage Excessively Low threshold, the TCM will not supply power to the solenoid valves and pressure regulators. A Diagnostic Trouble Code (DTC) is set when one of the diagnostic voltage thresholds is reached for a calibrated amount of time.