Fendt 1.2.71 – A022 (ECU, EMR2): A022, X810 - ECU, EMR2; diagnostics socket — CAN interface fault

This fault code indicates a communication failure on the SAE J1939 CAN bus network. Specifically, the CAN interface at the diagnostics socket (X810) is faulty or experiencing a disruption in data transfer, which may cause the tractor to experience reduced engine running characteristics (derated engine performance).

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• Fendt Farmer 400 Vario
• Fendt Favorit 700 Vario
• Fendt Favorit 900 Vario
• Fendt 300 Vario series
• Fendt 400 Vario series
• Fendt 700 Vario series
• Fendt 800 Vario series
• Fendt 900 Vario series

1. 1

   Check the CAN Bus terminating resistors located at the A013 circuit board and A009 actuator unit/positioner

2. 2

   Inspect the diagnostics socket (X810) physical pins and wiring for corrosion, pushed-out pins, or short circuits

3. 3

   Check the ECU EMR2 power supply, ground, and CAN wiring harness leading directly to the engine control unit

4. 4

   Run SERDIA diagnostics to read live data and confirm if the CAN fault is active or stored

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to safely test the CAN network resistance.

2. 2

   Test CAN Resistance

   Using a multimeter, probe the CAN High and CAN Low pins at the X810 diagnostic socket. A healthy CAN bus should read approximately 60 ohms.

3. 3

   Isolate the Resistors

   If the reading is 120 ohms, one terminating resistor is missing or broken. If the reading is out of bounds, check the specific terminating resistors at the A013 circuit board and the A009 actuator unit.

4. 4

   Repair Wiring

   If a resistor is faulty, or if there is a broken/shorted wire between the X810 socket, the A013 board, and the A022 ECU, repair the wiring harness.

5. 5

   Replace Components

   If the wiring and resistors test perfectly but the CAN interface fault persists, the CAN transceiver inside the A022 (EMR2 ECU) may be internally damaged, requiring ECU replacement or repair.

6. 6

   Clear Codes

   Reconnect the battery, turn the key on, and use the tractor's terminal or SERDIA software to clear the stored 1.2.71 fault code. Test drive to ensure full engine performance is restored.