John Deere 639.12 – PL1: Vehicle CAN Bus (500 kBd), High Error Rate

Generated when the control unit receives too many incorrect CAN Bus messages, cannot process all messages due to a CAN bus overload, or detects a general physical problem in the connection to the vehicle's CAN Bus network.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6140R
• 6150R
• 6170R
• 6190R
• 6210R

1. 1

   Inspect the physical CAN-BUS wiring harness connecting to the PL1 module for any chafing, damage, or loose connections.

2. 2

   Measure the resistance across the CAN network to ensure terminating resistors are intact (a defective resistor is a primary cause of high error rates).

3. 3

   Verify the battery and power supply voltage to the PL1 module to rule out voltage drops or spikes.

4. 4

   Monitor the CAN traffic using John Deere Service Advisor to see if another module is flooding the network and causing the PL1 module to overload.

1. 1

   Restart the Tractor

   Cycle the key and restart the engine. If the code was caused by a temporary CAN message overflow, it may clear on its own.

2. 2

   Update Software

   Connect John Deere Service Advisor and ensure the PL1 control software is updated to the latest version. Older software versions are known to struggle with CAN bus overloads.

3. 3

   Clean Connections

   Disconnect the PL1 Gear Shift Module. Inspect the pins for corrosion or pushed-back terminals. Clean the contacts with electrical contact cleaner and securely reconnect them.

4. 4

   Repair Wiring/Resistors

   If the diagnostic checks revealed a wiring short or a failed terminating resistor in the DirectDrive harness, repair the wiring or replace the resistor.

5. 5

   Replace the Module

   If the wiring, resistors, and software are all verified to be in good working order but the PL1 module continues to log a high error rate, the internal CAN transceiver within the PL1 Gear Shift Module has likely failed and the module must be replaced.