John Deere 520965.03 – OIC (Operator Interface Console): CAN BUS Terminating Resistor, CAN BUS Voltage Too High

The control software detects that the voltage on the CAN BUS circuit is excessively high, indicating that the CAN circuit is shorted to a power supply lead (e.g., a 12-volt source).

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6090MC
• 6090RC
• 6100MC
• 6100RC
• 6110MC
• 6110RC
• 5070M
• 5080M
• 5090M
• 5100M
• 6230
• 6330
• 6430
• 7130
• 7230
• 7530

1. 1

   Check CAN Bus Voltage: Use a multimeter to measure the voltage on the CAN High and CAN Low pins. A reading significantly higher than the standard CAN operating voltage (typically ~2.5V to 3.5V) confirms a short to power.

2. 2

   Test the Terminating Resistors: With the battery disconnected, measure the resistance across the CAN High and CAN Low lines. A healthy bus should read approximately 60 ohms (two 120-ohm resistors in parallel). If the reading is skewed, a resistor may be burnt or shorted.

3. 3

   Harness Inspection: Visually inspect the wiring harness connecting to the OIC and the terminating resistors. Look for rubbed-through insulation, pinched wires, or melted loom that could cause the CAN wires to touch a 12V supply line.

4. 4

   Isolate the Short: Disconnect modules on the affected CAN bus one by one to see if the high voltage drops. If disconnecting a specific module or terminating resistor clears the short, that component or its immediate wiring is the culprit.

1. 1

   Disconnect Power

   Always disconnect the negative battery cable before servicing CAN bus components to prevent module damage.

2. 2

   Locate the Terminating Resistor

   Depending on the tractor model and which specific CAN bus is affected (e.g., Vehicle CAN, Implement CAN), locate the terminating resistor. They are often found near the cab control unit, behind the instrument panel, or in the roof panel (e.g., components A61, A62, A010, or A053).

3. 3

   Repair Wiring (If Applicable)

   If the diagnostic checks revealed a short to a 12V power wire in the harness, cut out the damaged section of wiring and splice in new wire using weather-sealed crimp connectors.

4. 4

   Replace the Resistor

   If the terminating resistor itself has failed internally and is bridging power to the CAN lines, unplug the faulty resistor block and plug in the OEM replacement.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery, turn the key to the ON position, and use a John Deere Service ADVISOR tool (or equivalent scanner) to clear the OIC 520965.03 code. Verify that the code does not return upon startup.