Fendt 1.2.74 – EMR / EMR2 (Engine Management System ECU): CAN bus, wiring (EMR) — Cable broken, short circuit or serious CAN bus fault; CAN bus passive.

Critical communication failure on the CAN bus network, specifically a physical wiring issue (open circuit or short) preventing the Engine Management System from communicating properly with the rest of the tractor. Consequence: The running of the engine may be reduced (limp-home mode).

• 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
• Farmer 400 series
• Favorit 700 series
• Favorit 900 series
• 300 Vario (COM III)
• 400 Vario (COM III)
• 700 Vario (COM III)
• 800 Vario (COM III)
• 900 Vario (COM III)

1. 1

   Consult the 'Transmission Bus' circuit diagram and Chapter 2000 Reg. B for your specific tractor model

2. 2

   Check the voltage supply for the CAN bus on printed circuit board A013 and inspect fuses F039, F040, F041, and F046

3. 3

   Inspect the transmission bus terminating resistors on circuit board A013 and actuator unit A009 (should read ~60 ohms across high and low pins)

4. 4

   Test the CAN wiring harness between the EMR ECU (A022) and the Transmission ECU (A002) for continuity, shorts to ground, and shorts to power

5. 5

   Inspect the AMP Superseal or Minitimer connectors at the ECU for pushed-out pins, corrosion, or moisture ingress

1. 1

   Power Down

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

2. 2

   Fuse Replacement

   If any of the CAN bus supply fuses on board A013 (F039–F046) are blown, replace them and retest. If they blow again immediately, there is a hard short in the wiring.

3. 3

   Harness Repair

   If the diagnostic checks reveal a broken cable or short circuit between A022 and A002, locate the damaged section of the wiring harness. Repair the broken wires using OEM-approved CAN bus repair techniques (twisted pair wire, properly soldered and heat-shrunk) or replace the affected harness section.

4. 4

   ECU Verification

   If the wiring, fuses, and terminating resistors all test perfectly, the fault may be an internal hardware failure of the EMR2 ECU (A022) failing to broadcast on the bus.

5. 5

   Clear Codes

   After repairs are made, use the SERDIA diagnostics tool or the tractor's onboard terminal to clear the fault codes. Cycle the ignition OFF then ON, and test drive the tractor to ensure full engine performance is restored.