John Deere 000639.13 – BCU: Vehicle CAN BUS High Error Rate

The fault code 000639.13 signifies a '29-BIT CAN BUS, high error rate'. This indicates that a control module has detected a large number of corrupted or lost messages on the vehicle's Controller Area Network (CAN bus). It is an information alarm pointing to a communication system problem rather than a specific failed component.

• 6020
• 6120
• 6220
• 6320
• 6420
• 6420S
• 6520
• 6620
• 6820
• 6920
• 6920S
• 6020SE
• 6120SE
• 6220SE
• 6320SE
• 6420SE
• 6520SE
• 6120L
• 6220L
• 6320L
• 6420L
• 6520L
• 7020
• 8020
• 7x20
• 8x20

1. 1

   Check for other active or stored diagnostic trouble codes (e.g., BIF 000639.02), which take diagnostic priority

2. 2

   Inspect all relevant fuses, specifically fuse F04/13 for the CAN bus screen

3. 3

   Perform a cold boot by turning the machine completely off, disconnecting the battery, waiting a few minutes, and reconnecting to clear temporary glitches

4. 4

   Perform a CAN Bus Resistance Test (Power OFF) at the 9-pin diagnostic connector between CAN High (Pin C, Yellow) and CAN Low (Pin D, Green). Expected reading is ~60 Ω

5. 5

   Perform a CAN Bus Voltage Test (Power ON) between CAN High (Yellow) / CAN Low (Green) wires and chassis ground. Expected: CAN High 2.5V-3.5V, CAN Low 1.5V-2.5V

1. 1

   Review Diagnostic Findings

   The results from the resistance and voltage checks will guide the repair.

2. 2

   Address resistance faults

   If 120 Ω was measured, locate the open circuit or missing terminating resistor near the main ECUs. If 0 Ω was measured, visually inspect the harness for short circuits or disconnect modules one by one until resistance returns to normal.

3. 3

   Address voltage faults

   If the resistance test passes but voltage is incorrect, isolate the faulty ECU (transceiver) by disconnecting ECUs from the CAN bus one at a time while monitoring bus voltages to see if they return to normal.

4. 4

   Inspect wiring harness

   Regardless of meter readings, perform a thorough visual inspection of the CAN bus wiring harness. Look for chafing, pinch points near moving parts, damage from heat, or corrosion in connectors.

5. 5

   Isolate and repair

   Once a damaged section of wire or a faulty connector is found, repair or replace it. If a specific module is identified as the cause of the short or voltage anomaly, replace the module.