Fendt 1.2.D8 – Engine Control Unit (A051): A051 - ECU, engine control unit (EDC 7) - Incorrect voltage for internal 5 V reference source 2

The engine control unit (ECU) has detected that the 5-volt reference circuit supplying specific sensors is out of range (either pulled down to ground or shorted to voltage).

• 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
• Fendt 200 Vario (V / F / P)
• Fendt 309 Vario COM III
• Fendt 310 Vario COM III
• Fendt 311 Vario COM III
• Fendt 312 Vario COM III
• Fendt 411 Vario COM III
• Fendt 412 Vario COM III
• Fendt 413 Vario COM III
• Fendt 414 Vario COM III
• Fendt 415 Vario COM III
• Fendt 712 Vario COM III
• Fendt 714 Vario COM III
• Fendt 716 Vario COM III
• Fendt 718 Vario COM III
• Fendt 818 Vario COM III
• Fendt 820 Vario COM III
• Fendt 927 Vario COM III
• Fendt 930 Vario COM III
• Fendt 933 Vario COM III
• Fendt 936 Vario COM III
• Fendt 939 Vario COM III

1. 1

   Identify the affected circuit shared by fuel low pressure sensor B087 and foot throttle B055 or hand throttle B035.

2. 2

   Check sensor supply voltage at the connectors with ignition ON (should be exactly 5.0 VDC).

3. 3

   Isolate the short by disconnecting B087, B055, and B035 sensors one at a time to see if 5V reference returns.

4. 4

   Inspect the wiring harness connecting the A051 ECU to the sensors for chafing, breaks, or short circuits to ground.

1. 1

   Turn the ignition OFF.

2. 2

   Locate the sensors on the machine.

   B087 (Fuel low pressure sensor) on the right side of the engine, B055 (Foot throttle sensor) on the steering column unit, and B035 (Hand throttle sensor) on the multifunction armrest.

3. 3

   Repair damaged wiring or replace shorted sensors.

   Repair any damaged wiring found during the diagnostic phase. If a sensor was found to be internally shorted, replace the sensor.

4. 4

   Reconnect all sensor harnesses.

5. 5

   Turn the ignition ON and verify the 5V reference is stable.

6. 6

   Connect a diagnostic tool (SERDIA or Fendias) to the tractor.

7. 7

   Clear the fault code from the A051 ECU memory.

   Internal SERDIA code: FC:00DD