CONTROL GP-DIFFERENTIAL LOCK 3815360 - Caterpillar

Illustration 1 g01124024
Left Main Burner Mode SwitchThe left main burner mode switch has two inputs to the ECM. During normal operation, one of the inputs is open and the other input is returned (grounded) or both inputs are open. When a circuit is measured with a voltmeter, an open circuit will measure 5 DCV and a grounded circuit will measure approximately 0 DCV.Diagnostic code CID 935 FMI F12 is recorded when both burner mode switch inputs are returned (grounded). The possible causes of this diagnostic code are:
Signal circuit wire P860-OR (AUTO mode) is shorted to ground.
Signal circuit wire P856-GY (MANUAL mode) is shorted to ground.
The burner mode switch is malfunctioning.
The ECM has failed. This is unlikely.System Response:The results of this diagnostic code are:
Burner diagnostic lamp located below the screed walkway will be ON.
The ECM will not attempt to initiate the ignition cycle for the left main burner when this diagnostic code is active.Note: Ensure that the diagnostic code CID 935 FMI F12 is on hold and that the red diagnostic code present indicator on the conveyor ECM display is ON. If the diagnostic code is not present, toggle the switch until the switch is in the position where the diagnostic code is active.Test Step 1. Check The Auto Mode Signal Circuit For