John Deere 520426.07 – Tractor Equipment Control Unit (TEC): ISO BUS CAN BUS Fault Cab Roof Module (TEC) / Vehicle CAN Bus Error Counter High

The controller detects that too many incorrect CAN Bus messages are being transmitted, or no messages are being transmitted at all, indicating a critical communication breakdown or physical fault on the vehicle's CAN Bus network.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8245R
• 8400R
• 210K
• 210L EP
• 310K

1. 1

   Inspect the main CAN Bus wiring harness routing to the Cab Roof Module / TEC for chafing, pinches, or exposed wires

2. 2

   Disconnect the TEC/AIC module connectors and check for bent pins, corrosion, or moisture intrusion

3. 3

   Verify that the module is receiving proper operating voltage (12V) and has a clean, solid ground connection directly to the chassis/battery

4. 4

   With the battery disconnected, measure the resistance across the CAN High and CAN Low pins (should read approximately 60 ohms)

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Access the Module

   Locate the Tractor Equipment Control Unit (TEC) / Cab Roof Module (typically located in the cab roof liner or right-hand console depending on the tractor series).

3. 3

   Repair Wiring

   If the diagnostic checks revealed a short to ground, short to power, or open circuit on the CAN lines, repair the damaged section of the harness and replace any corroded connector pins.

4. 4

   Replace the Module

   If the CAN Bus wiring, terminating resistors, and power/ground supplies test perfectly, the TEC module itself has an internal transceiver failure and must be replaced.

5. 5

   Reassembly & Calibration

   Install the new module, reconnect the harnesses, and reconnect the battery.

6. 6

   Software Flash

   Have a John Deere dealer flash the correct control software (Group TEC - TEC Control Software) via Service ADVISOR to match the tractor's specific equipment configuration.