CONFIGURATION 4942104 - Caterpillar

Illustration 1 g00288434
Start Relay
The start relay is an output of the power train electronic control module (ECM). The activation and deactivation of the start solenoid is the purpose of the start relay. The start solenoid controls the starting motor.When the operator turns the key start switch to the START position and the power train ECM decides that all the starting conditions are satisfied, the power train ECM activates the start relay with a +battery signal. The +battery voltage is present at connector contact J1-40 of the power train ECM. The operator must also have the direction switch in the NEUTRAL position. When all starting conditions are satisfied, the power train ECM sends a +battery signal to the connector contact J1-8 for the start relay and engine cranking begins.Terminal 3 of the start relay connects to a +battery source. Terminal 4 connects to the start solenoid.Reference: For more information on the neutral start function, refer to Systems Operation, "Power Train Electronic Control System" for the machine that is being serviced.Reference: For more information on the function of the power train ECM, refer to Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.