AUTOMATIC TRANSMISSION – GM 5L40-E DESCRIPTION AND OPERATION 44-1-55 Inputs and Outputs The sensor signals allow the EAT ECU to monitor the transmission operation. The ECU processes the incoming signals and compares this information with data stored in its memory. If the received signals are not within the stored values, the ECU will make adjustments to the transmission operation using the solenoids to provide optimum driveability and performance. The sensor inputs provide the EAT ECU with a constant update of the operating condition of the transmission and the engine. The ECU compares this input data with mapped information stored in its memory and will make any required adjustment to the operation of the transmission by operating the solenoids. The EAT ECU uses three harness connectors for all input and output information.