John Deere 000084.09 – SSU / CCU: Wheel Speed Sensor Communication Fault

The system has detected a communication issue on the CAN bus where a control unit is not receiving the expected wheel speed (ground speed) message from the wheel speed sensor. The abnormal update rate indicates that the data from the sensor is missing, invalid, or not being received at the correct interval.

• 9230
• 9330
• 9430
• 9530
• 9630
• 8230T
• 8330T
• 8430T
• 7630
• 7730
• 7830
• 7930
• 8245R
• 6420
• 9560 STS
• 9660 STS
• 9760 STS
• 9860 STS
• 329E
• 333D

1. 1

   Restart the vehicle, as this can sometimes reset communication messages and clear the code

2. 2

   Check specific fuses related to the controller's power supply (e.g., fuse F23 for the SSU in 9030 series tractors)

3. 3

   Visually inspect the wheel speed sensor, wiring harness, and all related connectors for physical damage, corrosion, chafing against the frame, or loose connections

4. 4

   Verify that there is 12V power and a solid ground connection at the sensor's connector

5. 5

   Perform a circuit load test on the signal, power, and ground wires using a small 12V light bulb to ensure they can carry a current

6. 6

   With the system powered down, measure the resistance between the CAN High and CAN Low wires (typically yellow and green); it should be approximately 60 ohms

7. 7

   With the system powered on, check the DC voltage of the CAN lines; CAN High and CAN Low should both be around 2.5V

1. 1

   Locate the Sensor

   The wheel speed sensor is generally located on the transmission housing, final drive, or differential housing. On an 8245R with an IVT, it's on the upper left side of the transmission, while on a powershift model, it's on top of the differential housing behind the SCV stack. On a 6420, it is located directly above the rear axle. For some track loaders, accessing the sensor requires removing the track.

2. 2

   Disconnect and Clean

   Disconnect the sensor's electrical connector. Clean the sensor and the surrounding area to remove any debris or metal filings that could interfere with its reading.

3. 3

   Test the Sensor

   If the wiring checks out, the sensor itself may be faulty. It can be tested with a multimeter or a diagnostic tool to confirm its output.

4. 4

   Replace the Sensor

   If the sensor is determined to be faulty, replace it with a new OEM part. On some machines, a small amount of oil may be lost when the sensor is removed.

5. 5

   Address CAN Bus Issues

   If the sensor and its direct wiring are not the cause, the problem lies deeper within the CAN bus. This could be a damaged wire elsewhere in the harness, a faulty terminating resistor, or a malfunctioning control unit. Tracing these issues can be complex and may require specialized diagnostic tools like John Deere Service ADVISOR™.

6. 6

   Calibration

   In some instances, particularly on compact track loaders, a new wheel speed sensor may need to be calibrated after installation.