John Deere 520426.07 – Cab Roof Module (RLC / TEC), Operator Interface Console (OIC), Armrest Interface Control Unit (AIC), or Main Control Module (CCU): Vehicle CAN Bus Error Counter High / CAN BUS Message Issue

Triggered when the error counter for the vehicle's Controller Area Network (CAN) Bus reaches an unusually high level, indicating persistent communication errors such as too many incorrect CAN Bus messages being transmitted, or no messages being transmitted at all.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 9470RT
• 9520RT
• 9570RT
• 210K Tractor Loader
• 210L EP Tractor Loader
• 310K Backhoe Loader

1. 1

   Monitor CAN Bus Traffic: Use John Deere Service ADVISOR or compatible diagnostic software to monitor the CAN Bus traffic. Look for sources of errors such as electrical noise or conflicts.

2. 2

   Check for Incompatible Devices: Verify if any aftermarket devices, monitors, or incorrectly configured implements are plugged into the CAN Bus (such as ISO BUS connectors), as these can flood the network and cause high error counts.

3. 3

   Inspect Wiring and Connectors: Physically inspect the CAN Bus wiring harness, particularly the routing to the Cab Roof Module (RLC), OIC, or AIC. Look for chafed wires, pinched harnesses, or corroded connector pins that could cause intermittent shorts to ground or power.

4. 4

   Cross-Reference Codes: Check for other active CAN Bus voltage codes (e.g., 520542.03 - CAN Bus Circuit Voltage High or 520543.04 - CAN Bus Circuit Voltage Low). The presence of these codes alongside 520426.07 usually pinpoints a hard electrical short rather than a module failure.

1. 1

   Isolate the Network

   Disconnect any aftermarket or non-essential ISO BUS implements/monitors from the tractor. Clear the codes and see if the error counter normalizes.

2. 2

   Repair Wiring

   If the diagnostic software or physical inspection reveals a fault in the wiring harness (e.g., between the Cab Roof Module and the Main Controller), repair the damaged wires or replace the affected harness section. Ensure all connector pins are clean and seated tightly.

3. 3

   Module Replacement

   If the wiring tests perfectly (terminating resistors measure 60 ohms across the CAN High and CAN Low lines) and the network is still crashing, the module logging the code (e.g., the Cab Roof Module or OIC) may have an internal transceiver failure. Replace the faulty module.

4. 4

   Reconfigure and Test

   After replacing any wiring or modules, ensure all devices on the network are properly configured. Reset the error counter via the diagnostic tool.

5. 5

   Final Validation

   Turn the key switch ON and run the engine. Monitor the CAN Bus operation to ensure the error rate remains within specified parameters and the code does not return.