John Deere 639.14 – Various (HCC, FCC): Vehicle CAN BUS, Very High Error Rate / CAN Bus Error Limit Exceeded

A standard J1939-style network communication error indicating the control unit logging the code is receiving an excessive number of incorrect CAN BUS messages, or has detected a general physical problem with the CAN BUS network (such as a short circuit, open circuit, electrical interference, or bus overload). The affected module will typically limit or disable its functions to prevent erroneous operations.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6M
• 6R
• 6090MC
• 6100MC
• 6110MC
• 8R
• 8RT
• 8225R
• 8320R
• 8400R
• 9R
• 9RT
• 9230
• 9330
• 9430
• 9530
• 9630
• 5090M
• 5100M
• 5115M

1. 1

   Check CAN Bus Resistance: Disconnect the battery. Use a multimeter to measure the resistance between the CAN High and CAN Low pins at the diagnostic connector. A healthy CAN bus should read approximately 60 ohms. If it reads 120 ohms, one termination resistor is missing or broken. If it reads near 0 ohms, the CAN lines are shorted together.

2. 2

   Inspect Wiring and Connectors: Visually inspect the main vehicle CAN bus harness for chafing, rodent damage, or pinched wires. Check the connectors at the HCC (rear of the tractor) and FCC (front dash/cab area) for water ingress, bent pins, or corrosion.

3. 3

   Isolate the Faulty Node: Because a single failed module can flood the CAN bus and cause other modules to log 000639.14, disconnect modules one by one (starting with the one logging the code, e.g., the HCC or FCC). If the CAN bus error rate drops and communication restores for the rest of the tractor after unplugging a specific module, that module is internally shorted and is the culprit.

4. 4

   Check Power and Ground: Verify that the module logging the code is receiving proper unswitched and switched supply voltage, and has a clean ground. Low voltage can cause a module to drop off the network.

1. 1

   Disconnect Power

   Turn off the key and disconnect the negative battery cable.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short or open circuit in the harness, splice and heat-shrink the damaged CAN High or CAN Low wires, or replace the damaged harness section.

3. 3

   Replace Termination Resistors

   If the network resistance was incorrect and a termination resistor is found to be burnt or corroded, replace it.

4. 4

   Replace the Faulty Module

   If the wiring is perfectly intact but the HCC or FCC is internally shorting the CAN bus, unbolt the module, disconnect its harness, and install a replacement unit.

5. 5

   Reconfigure and Update

   Reconnect the battery. Use John Deere Service ADVISOR to clear the stored 000639.14 codes. If a new HCC or FCC was installed, it must be calibrated and flashed with the latest firmware to match the tractor's VIN and configuration.