John Deere 639.12 – Range Module Direct Drive: Vehicle CAN Bus (500 kBd), High Error Rate

The control software is receiving an excessively high number of incorrect CAN Bus messages and cannot process them all, indicating a general communication breakdown on the 500 kBd Vehicle CAN Bus network.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R

1. 1

   Verify CAN Bus connections by inspecting the wiring harness connecting to the PL3 Range Module to ensure all connectors are secure, free of corrosion, and not physically damaged.

2. 2

   Test the CAN-BUS terminating resistors on the network, as a defective resistor can cause signal reflection and high error rates.

3. 3

   Inspect CAN Bus traffic using a John Deere Service ADVISOR diagnostic tool to monitor for excessive errors, interference, or network overload.

4. 4

   Check if the PL3 control software is up-to-date, as older software versions can cause internal initialization faults or watchdog errors that flood the CAN bus.

1. 1

   Update Software

   If a software update is available for the PL3 Range Module, flash the module to the latest version to rule out internal software bugs causing CAN overload.

2. 2

   Repair Wiring

   If the diagnostic checks reveal chafed wires, shorts to ground, or loose pins at the PL3 connector, repair or replace the affected section of the CAN bus wiring harness.

3. 3

   Replace Terminating Resistors

   If a terminating resistor tests out of specification (the network should typically read ~60 ohms across CAN High and CAN Low with the battery disconnected), replace the faulty resistor.

4. 4

   Replace the Module

   If the wiring is intact, the software is updated, and the CAN network is otherwise healthy but the PL3 module continues to drop off the bus or flood it with errors, the PL3 Range Module Direct Drive has an internal hardware fault and must be replaced.