STARTING MOTOR GP-ELECTRIC 3639837 - Caterpillar

Illustration 1 g03345445
Schematic of the "Brake Pump Pressure" sensorThis diagnostic code is associated with the "Brake Pump Pressure" sensor. The FMI 03 diagnostic code means that the Brake ECM has determined that the voltage or duty cycle for the position sensor is above normal. The pressure sensor is an active analog sensor. The sensor sends a voltage signal to the Brake ECM to indicate the level of pressure that is available for the braking the truck.The possible causes of this diagnostic code are listed below:
The signal circuit for the sensor is open.
The signal circuit for the sensor is shorted to the +battery circuit.
The sensor has failed.
The power circuit or the ground circuit has failed.
The Brake ECM has failed. This situation is unlikely.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, that all connections are secure and that all connections are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 1962 FMI 03 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.Test Step 1. CHECK FOR POWER AT THE SENSOR.
Turn the key start switch and the disconnect switch to the ON position.
Disconnect the harness connector from the sensor.
At the machine harness connector for the sensor, measure the voltage from contact A of the power supply (113-OR) and the contact of the ground (wire J765-BU).Expected Result:The measurement of the supply voltage is 24.0 1.0 VDC.Results:
OK - The measurement of the supply voltage is 24.0 1.0 VDC. The power supply for the sensor is correct. Proceed to Test Step 2.
NOT OK - The measurement of the supply voltage is less than 24.0 1.0 VDC. The power supply circuit in the machine harness has failed.Repair: The wire of the return circuit J765-BU or the wire of the supply circuit 113-OR has a bad connection or an open in the machine harness. Examine all of the connections that are in the circuit. Ensure that the connections are clean, that all connections are secure and that all connections are in good condition.STOPTest Step 2. CHECK FOR AN OPEN IN THE SENSOR CIRCUIT.The connector of the machine harness remains disconnected from the sensor.
Turn the key start switch and the disconnect switch to the OFF position.
At the machine harness connector of the sensor, place a wire (jumper) between contact B the return contact of the sensor (wire J765-BU) and contact C the signal contact of the sensor (wire E566-PU).
Disconnect the machine harness connectors J1 and J2 from the Brake ECM.
At the harness connectors for the Brake