Fendt 1.2.2A – A002 / A021: CAN message fault from the Enhanced Control Module (A002) to the EDC Control Module (A021) - Engine brake function

Communication timeout or interruption on the transmission bus (G-BUS) or comfort bus between the Enhanced Control Module (A002) and the EDC Control Module (A021), causing the engine/exhaust brake to become non-operational.

• 409 Vario
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1. 1

   Verify the fault display message on the dash panel and check if the exhaust/engine brake is indeed non-operational

2. 2

   Check voltage supply to the CAN-Bus on fuse board A013 (check fuses F040, F041, or related EDC fuses) to ensure neither module has lost power

3. 3

   Using an adapter box and a multimeter, check the CAN bus wiring (Transmission-BUS / G-BUS) between the EST Control Module (A002) and the EDC Control Module (A021)

4. 4

   Look for other CAN timeout codes (like 1.2.2B, 1.2.2C, or 1.1.B0) which might indicate a broader transmission bus failure rather than an isolated engine brake signal issue

1. 1

   Disconnect Battery

   Always disconnect the battery before servicing ECU wiring.

2. 2

   Inspect Harness

   Physically inspect the wiring harness connecting the A002 and A021 modules. Look for chafing, pinched wires, or corrosion, particularly where the harness routes near the transmission and engine block.

3. 3

   Clean Connectors

   Disconnect the harness at both the A002 (EST) and A021 (EDC) modules. Clean the pins with electrical contact cleaner and check for pushed-out or bent pins.

4. 4

   Test Continuity

   Measure the resistance of the CAN High and CAN Low wires between the two modules. Repair any open circuits or shorts to ground/power.

5. 5

   Test CAN Resistors

   Verify the terminating resistance of the CAN bus network (typically 60 ohms across CAN High and CAN Low when the battery is disconnected).

6. 6

   Module Replacement

   If the wiring, fuses, and connections are perfectly intact, the CAN transceiver inside either the A002 or A021 module may have failed. The module will need to be replaced and reprogrammed (EOL programming via FENDIAS/SERDIA diagnostic software).