GEAR GP-OUTPUT TRANSFER 3649701 - Caterpillar

Illustration 1 g01252059
Left rear wheel speed sensor circuitThe CID 0607 FMI 02 diagnostic code is recorded when the brake ECM compares certain machine conditions to left rear wheel speed sensor data. The ECM will issue this diagnostic code if the sensor data is not within certain parameters.Possible sensor conditions that can cause this diagnostic code are listed:
Power supply for the sensor is faulty.
Signal circuit is shorted to ground.
Mechanical problems with the speed sensor.
The sensor has failed.
The ECM has failed. ECM failure is unlikely.Before performing the following test steps, perform the following visual inspections:
Verify that the sensor is mounted securely.
Verify that the connectors are securely connected.If the sensor mount and the contacts secure, but CID 0607 FMI 02 is active, proceed to the first test step.Test Step 1. CHECK POWER SUPPLY CIRCUIT OF THE SENSOR
Disconnect the sensor from the harness.
Turn the keyswitch and the disconnect switch to the ON position.
At the harness connector for the sensor, measure the voltage between contact A (wire C985-BU) and the ground contact B (wire A235-BK).Expected Result:The voltage is 8V. Results:
OK - The voltage is 8V. The supply circuit is correct. Proceed to Test Step 2.
NOT OK - The voltage is not 8V. Proceed to Test Step 2.Test Step 2. CHECK FOR AN OPEN SIGNAL WIRE IN THE HARNESS.Note: The sensor remains disconnected from the harness. The disconnect switch and the keyswitch remain in the OFF position.
Disconnect the harness ECM connectors J1 and J2 from the ECM.
At the harness connector for the sensor, connect a jumper between contact B (wire A235-BK) and contact C (wire 769-BU).
At the harness ECM connectors, measure the resistance from contact J1-45 (wire A235-BK) to J2-34 (wire 769-BU).Expected Result:The resistance is less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. The circuit is correct. Proceed to Test Step 3.
NOT OK - The resistance is more than 5 ohms. There is an open wire in the harness or a faulty connection in the harness. Repair: Consult the Electrical Schematic for this machine. Check all harness connectors in the sensor circuit. Ensure that the contacts of the connectors are clean, connected, and secure. After checking the connectors, repeat this test step. If the problem remains, check the wiring for a broken wire. Repair or replace the harness.STOPTest Step 3. CHECK FOR A SHORT IN THE SIGNAL CIRCUIT OF THE HARNESS.Note: The harness connectors remain disconnected from the sensor and the ECM. Remove the jumper that was installed in the last step. The keyswitch and the disconnect switch remain in the OFF position.
At the harness connector for the ECM, measure the resistance between contact J2-34 (wire 769-BU) to all sources of ground on connectors J1 and J2.Expected Result:The resistance is greater than 5000 ohms.Results:
OK - The resistance is greater than 5000 ohms. Proceed to Test Step 4.
NOT OK - A resistance is less than 5000 ohms. There is short between signal contact J2-34 (wire 769-BU) and one of the grounded wires in the harness.Repair: Repair or replace the harness.STOPTest Step 4.