John Deere 639.14 – XMC: Vehicle CAN BUS, Very High Error Rate

The control unit receives an excessive number of incorrect CAN BUS messages, or detects a general connectivity problem within the vehicle's CAN BUS network, typically caused by electrical interference, faulty wiring, defective network components, or missing/failed CAN BUS terminating resistors.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7210R
• 7230R
• 7250R
• 7270R
• 7290R
• 8235R
• 8260R
• 8285R
• 8310R
• 8335R
• 8360R
• 9330
• 9430
• 9530
• 9630
• S-Series
• T-Series
• W-Series
• STS

1. 1

   Inspect all CAN BUS wiring and connectors leading to the XMC for signs of damage, corrosion, or loose connections.

2. 2

   Test the CAN BUS terminating resistors at both ends of the network (should measure 60 ohms across CAN High and CAN Low pins with battery disconnected).

3. 3

   Measure battery voltage to ensure the XMC receives a stable supply voltage above 11 volts.

4. 4

   Check the software package version via the CommandCenter (address XMC 237) for outdated firmware.

1. 1

   Secure Connections

   Clean and securely reconnect any loose or corroded CAN BUS connectors at the XMC module and the StarFire receiver.

2. 2

   Repair Wiring

   If diagnostic testing reveals breaks or high resistance in the wiring harness, repair or replace the affected CAN BUS wiring.

3. 3

   Replace Terminators

   If a terminating resistor is burnt out or missing, plug in a new OEM CAN terminator to restore network integrity.

4. 4

   Replace the XMC Module

   If the wiring and resistors are intact but the XMC continues to broadcast a high error rate or fails to communicate, the Steering Control Unit itself has failed internally and must be replaced.

5. 5

   Update and Calibrate

   After replacing the XMC or repairing the network, apply any available software updates via Service ADVISOR, then recalibrate the steering sensors (Wheel Angle Sensors) on flat, smooth, and hard ground by entering the tractor's technical mode via the armrest controls.