Fendt 1.2.2C – EST Control Module (A002) / EDC Control Module (A021): CAN message failure from the EST Control Module to the EDC Control Module regarding the Exhaust brake

The CAN bus connection or communication between the Fendt enhanced control unit and the engine brake system is interrupted, causing the exhaust brake / engine brake to be completely non-operational.

• 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 series
• Fendt Favorit 700 series
• Fendt Favorit 900 series
• Fendt 300 Vario series
• Fendt 400 Vario series
• Fendt 700 Vario series
• Fendt 800 Vario series
• Fendt 900 Vario series

1. 1

   Check Fuses: Verify the voltage supply to the CAN-Bus on fuse board A013. Specifically, check fuses F040 and F041, as a blown fuse here will disrupt the transmission bus.

2. 2

   Inspect Wiring and Connectors: Check the CAN-Bus wiring for a short circuit to earth or broken wires between the EST Control Module (A002) and the EDC Control Module (A021).

3. 3

   Pin-to-Pin Continuity Test: Using an adaptor box with the ignition 'ON', check the specific CAN connections. Test the continuity from the EST module (A002, Connector X031, Pins 4 and 5) to the EDC control module (A021, Connector X048, Pin 11 and corresponding CAN pin).

4. 4

   Review Circuit Diagrams: Consult the 'EDC Control', 'Transmission - BUS', and 'Comfort-BUS' electrical diagrams for your specific chassis number to trace the exact routing of the engine brake circuit.

1. 1

   Turn off the tractor and disconnect the battery

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Locate fuse board A013 and replace any blown fuses

   Locate fuse board A013 and replace any blown fuses (F040, F041).

3. 3

   Access the wiring harness

   Access the wiring harness connecting the EST (A002) and EDC (A021) modules.

4. 4

   Repair or replace damaged CAN bus wires

   Repair or replace any damaged, corroded, or broken CAN bus wires found during the continuity test.

5. 5

   Replace and reprogram EST or EDC module

   If the wiring and fuses are intact but the modules fail to communicate, the fault may lie within the EST or EDC module itself, requiring replacement and EOL (End-Of-Line) reprogramming.

6. 6

   Inspect the exhaust brake valve/actuator

   If the communication is verified but the physical brake fails to actuate, inspect the exhaust brake valve/actuator for mechanical failure.

7. 7

   Clear the fault code and test

   Reconnect the battery, turn the ignition on, and use the FENDIAS or SERDIA diagnostic software to clear the fault code and test the engine brake function.