John Deere 639.14 – Range Module Direct Drive (PL3): Vehicle CAN Bus (500 kBd), Very High Error Rate

The control software detects an excessive number of incorrect CAN Bus messages, indicating a general problem with the vehicle's CAN Bus connection. This disruption is typically caused by electrical interference, faulty wiring, signal degradation, or defective network components.

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

1. 1

   Verify CAN Bus connections by inspecting all wiring and connectors routing to the PL3 module for damage, corrosion, or looseness

2. 2

   Inspect CAN Bus termination resistors to ensure they are present and functioning correctly

3. 3

   Use John Deere diagnostic tools to monitor CAN Bus traffic for excessive errors or electrical interference

4. 4

   Systematically check all modules connected to the CAN Bus to see if another module is crashing the network

5. 5

   Verify if the PL3 control software is up-to-date

1. 1

   Visual Inspection & Cleaning

   Start by visually inspecting the CAN BUS harness routing to the PL3 Range Module. Look for chafing, pinched wires, or loose connectors. Disconnect the connectors at the PL3 module and clean them using electrical contact cleaner.

2. 2

   Test Network Resistance

   With the battery disconnected, measure the resistance across the CAN High and CAN Low pins. It should read approximately 60 ohms if both termination resistors are intact. If it reads 120 ohms, one terminator is faulty or there is an open circuit.

3. 3

   Repair Wiring/Terminators

   Repair or replace any damaged wiring, corroded connectors, or faulty CAN terminators found during your testing.

4. 4

   Isolate Defective Modules

   If the wiring and terminators are good but the high error rate persists, systematically disconnect other CAN BUS modules one by one to isolate if another defective part is contributing to the high error rate.

5. 5

   Software Update

   Apply any available firmware or software updates to the PL3 control unit and other CAN BUS modules to ensure they are operating with the latest fixes.

6. 6

   Module Replacement

   If the high error rate is isolated directly to a hardware fault within the PL3 module itself, replace the Range Module Direct Drive (PL3).

7. 7

   Clear and Test

   Clear the fault codes using a diagnostic tool and test drive the tractor to ensure the CAN Bus error rate has normalized and the transmission operates correctly.