Fendt 1.2.C4 – Engine Control Unit (ECU) A051 / Bosch EDC 7: Pump control unit (injection pump) (EDC). Fault in CAN communication to pump control unit

Communication breakdown on the CAN bus network between the main engine controller and the injection pump's dedicated control module. The tractor's safety protocol forces the engine into a restricted operating mode, locking the engine at an idle speed of 720 RPM.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• 916
• 920
• 924
• 926
• 930
• 933
• 936
• 815
• 817
• 818
• 711
• 712
• 714
• 716
• 409
• 410
• 411
• 412
• 309
• 310
• 311
• 312

1. 1

   Consult the EDC control circuit diagram and check the CAN bus communication lines between the A051 (EDC 7 Engine Control Unit) and the A020 (Injection Pump Control Unit).

2. 2

   Inspect the wiring harness connectors at both the EDC 7 and the injection pump for moisture, corrosion, backed-out pins, or chafed wires.

3. 3

   Use the FENDIAS diagnostic software (via the X412 diagnostic connector) to read the parameters from both the Engine and Injection pump control modules. Note that fault codes in the A051 module can only be deleted using SERDIA/FENDIAS after the physical error is corrected.

1. 1

   Safety First

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical shorts while working on the CAN bus system.

2. 2

   Locate Components

   Locate the A051 Engine Control Unit (often located near the right entrance step/battery case depending on the model) and the A020 Injection Pump.

3. 3

   Harness Testing

   Disconnect the harness from both the EDC 7 and the injection pump. Use a multimeter to perform a continuity test on the CAN High and CAN Low wires between the two modules. Test for short-to-ground and short-to-voltage.

4. 4

   Repair Wiring

   If resistance is high or a break is found, repair or replace the damaged section of the engine wiring harness.

5. 5

   Module Assessment

   If the wiring harness tests perfectly, the fault lies internally within either the A020 Pump Control Unit (which often requires replacing/rebuilding the injection pump) or the A051 EDC 7 module.

6. 6

   Reassembly and Clearing

   Reconnect all harnesses and the battery. Connect the FENDIAS diagnostic tool, clear the 1.2.C4 fault code from the A051 memory, and start the engine to verify if the 720 RPM idle restriction has been lifted.