JOYSTICK GP 1868608 - Caterpillar

Illustration 1 g01252059This diagnostic code is recorded when the ECM compares certain machine conditions and the data received from the left 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 ECM has failed. This is unlikely.Note: Before performing the following Test Steps, check to see that the speed sensor is mounted securely. If the speed sensor mount is secure and the CID 0607 FMI 02 code is active, proceed to Test Step 1.Test Step 1. CHECK POWER SUPPLY CIRCUIT FOR THE SENSOR
Disconnect the sensor from the machines harness.
Turn the key start switch and the disconnect switch (if equipped) to the ON position.
At the machine harness connector for the sensor, measure the voltage between contact A (wire C985-BU(Blue)) and the ground contact B (wire A235-BK(Black)). Expected Result:The DC supply voltage measures 8 volts. Results:
OK - The DC supply voltage is 8 volts. The supply circuit is correct. Proceed to Test Step 2.
NOT OK - The DC supply voltage is not 8 volts. Proceed to Test Step 3.Test Step 2. CHECK THE RESISTANCE OF THE CASE OF THE SENSORNote: The sensor remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch (if equipped) to the OFF position.
At the sensor connector, measure the resistance between contact A and the case of the sensor, between contact B and the case of the sensor and between contact C and the case of the sensor. Expected Result:The resistance for each measurement is greater than 10,000 ohms. Results:
OK - The resistance for each measurement is greater than 10,000 ohms. The sensor is not internally shorted. Proceed to Test Step 3.
NOT OK - The resistance is NOT greater than 10,000 ohms. The speed sensor is shorted internally.Repair: Replace the sensor.STOPTest Step 3. CHECK FOR AN OPEN SIGNAL WIRE IN THE MACHINE HARNESS.Note: The sensor remains disconnected from the machine harness.
The key start switch and the disconnect switch (if equipped) remain in the OFF position.
Disconnect the machine harness ECM connectors J1 and J2 from the ECM.
At the machine harness connector for the sensor, connect a jumper between contact B (wire A235-BK(Black)) and contact C (wire 769-BU(Blue)).
At the machine harness ECM connectors, measure the resistance from contact J1-45 (wire A235-BK(Black)) to J2-34 (wire 769-BU(Blue)). Expected Result:The resistance measurement is less than 5 ohms.Results:
OK - The resistance measurement is less than 5 ohms. The circuit is correct. Proceed to Test Step 4.
NOT OK - The resistance measurement is more than 5 ohms. There is an open wire in the machine harness or there is a faulty connection in the machine 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