Main Relay

The main relay is located in the engine compartment fusebox and supplies battery voltage to the EAT ECU, in addition to other vehicle components. The main relay is energized by the ECM when the ignition is switched on.

When the ignition is switched off, the ECM will maintain the main relay in an energized state for several minutes. This allows for cooling fan operation to continue after the engine has been switched off and allows other vehicle ECU's to remain active. The EAT ECU remains active for a short period after the ignition is switched off to allow EEPROM fault code data to be stored.

In the event of a main relay failure, any of the following symptoms may be observed:

• The gearbox will be locked in 4th gear (limp home mode).
• No CAN communications will be available.