COMMON AR 3904350 - Caterpillar

Illustration 1 g02755916
Connections of the right and left rear wheel speed sensors
This diagnostic code is recorded when the ECM compares certain machine conditions and the data received from the right rear wheel speed sensor. 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:
The power supply for the sensor is faulty.
The signal circuit is shorted to ground.
The speed sensor is not installed correctly.
The speed sensor has failed.
The Brake ECM has failed. An ECM failure is unlikely.Before performing the following test steps, perform the following visual inspections:
Verify that the speed sensor is mounted securely.
Verify that the contacts of the harness connectors used in the solenoid circuit are connected to the contacts and are secure.If the speed sensor mount and the contacts secure, but the CID 0608 FMI 02 code is active, proceed to the first test step.Test Step 1. CHECK POWER SUPPLY CIRCUIT FOR THE SENSOR
Disconnect the sensor from the machines harness.
Turn the keyswitch and the disconnect switch (if equipped) to the ON position.
At the harness connector for the sensor, measure the voltage between contact A (wire 799-WH(White)) and the ground contact B (wire J765-BU(Blue)). Expected Result:The DC supply voltage measures 10 VDC. Results:
OK - The DC supply voltage is 10 VDC. The supply circuit is correct. Proceed to Test Step 2.
NOT OK - The DC supply voltage is not 10 VDC. Proceed to Test Step 2.Test Step 2. CHECK FOR AN OPEN SIGNAL WIRE IN THE HARNESS.
The keyswitch and the disconnect switch (if equipped) 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 J765-BU(Blue)) and contact C (wire 770-GN(Green)).
At the harness ECM connectors, measure the resistance from contact J2-63 (wire J765-BU(Blue)) to J2-33 (wire 770-GN(Green)). 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 there is a faulty connection in the harness. Repair: Consult the complete electrical system schematic for this machine. Check all harness connectors that are in the speed 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 circuit 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 (if equipped) remain in the OFF position.
At the harness connector for the ECM, measure the resistance between contacts J2-33 (wire 770-GN(Green)) to all sources of ground on connectors J1 and J2. Expected Result:The