Engine Speed and Throttle Monitoring The ECM constantly supplies the EAT ECU with information on engine speed and throttle angle through messages on the CAN. The EAT ECU uses this information to calculate the correct and appropriate timing of shift changes. If the messages are not received by the ECM, the EAT ECU will implement a backup strategy to protect the transmission from damage and allow the vehicle to be driven. In the event of an engine speed signal failure, any of the following symptoms maybe observed: l Decrease in fuel economy l Increase in engine emissions. In the event of a throttle position signal failure, any of the following symptoms maybe observed: l Harsh shift changes l No kickdown l Torque reduction request inhibited.