Fendt A.1.85 – Enhanced Control ECU (A002): Short circuit in the voltage supply for the steering angle sensor and pressure switch.

Indicates a short circuit in the shared voltage supply affecting the B094 steering angle sensor and S088 Auto-Guide pressure switch. When this fault is active, the 4WD and differential lock auto systems will become inoperable.

• 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 300 Vario (COM III)
• Fendt 400 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 700 Vario (COM III)
• Fendt 712 Vario (COM III)
• Fendt 714 Vario (COM III)
• Fendt 716 Vario (COM III)
• Fendt 718 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 815 Vario (COM III)
• Fendt 817 Vario (COM III)
• Fendt 818 Vario (COM III)
• Fendt 820 Vario (COM III)
• Fendt 900 Vario (COM III)

1. 1

   Review electrical wiring diagram Sheet 39 (and Sheet 33 for B094 ground/signal lines) to map the voltage supply for the B094 and S088 components.

2. 2

   Inspect the wiring harness routing to the front axle (B094) and Auto-Guide valve block (S088) for chafed insulation, pinched wires, or melted conduit.

3. 3

   Disconnect the B094 sensor and the S088 pressure switch one at a time to see if the short circuit clears, isolating an internally shorted component.

1. 1

   Disconnect Battery

   Always disconnect the tractor's battery before repairing electrical shorts to prevent ECU damage.

2. 2

   Repair Wiring

   If the diagnostic checks revealed damaged wiring on Sheet 39's voltage supply circuit, cut out the damaged section and solder/heat-shrink new wiring, or replace that section of the harness.

3. 3

   Replace Faulty Components

   If the wiring is intact but the B094 sensor or S088 switch is internally shorted, remove and replace the faulty component.

4. 4

   Calibrate the Steering Angle Sensor

   If the B094 steering angle sensor is replaced or its mounting is disturbed, you must perform a calibration. The Auto-Guide system will not track a straight line if the B094 center position and steering angles are not precisely calibrated in the terminal.

5. 5

   Clear Codes

   Reconnect the battery, turn the ignition on, and use the tractor's terminal or FENDIAS diagnostic software to clear the stored A.1.85 fault code.