Fendt 0A.1.X3 – Hydraulic/Valve CAN BUS: Overvoltage, safe (where U > 18 V)

The system has detected that the voltage supplied to the specified auxiliary control valve has exceeded 18 volts. As a safety measure, the affected valve automatically moves to the neutral position and locks.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 200 V, F, P Vario series
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III) and 700 SCR series
• Fendt 800 Vario (COM III) and 800 SCR series
• Fendt 900 Vario (COM III) and 900 SCR series

1. 1

   Check System Charging Voltage: Start the tractor and use a multimeter to measure the voltage at the battery. If the voltage spikes above 15-18V while running, the alternator's voltage regulator has failed and is overcharging the system.

2. 2

   Inspect the Wiring Harness: If the alternator is outputting a normal 14V, inspect the wiring harness leading to the rear and middle auxiliary control valves (refer to Circuit Diagram Sheet 8 in the Fendt manual). Look for a 'short to power' where the valve signal wire might be rubbing against a higher-voltage supply line.

3. 3

   Check ECU/Terminal Connections: Verify the connections at the hydraulic CAN bus and the main ECU to ensure no pins are bridged or corroded.

1. 1

   Address the Charging System

   If your multimeter confirms the system is running at >18V, remove and replace the alternator or the alternator's internal voltage regulator.

2. 2

   Repair Wiring

   If the overvoltage is localized to the valve harness, locate the short circuit in the wiring loom (Circuit Diagram Sheet 8) and splice/heat-shrink the damaged wires.

3. 3

   Clear the Code

   Once the voltage is stabilized below 18V, use the tractor's terminal or the FENDIAS diagnostic software to clear the stored 0A.1.X3 fault code.

4. 4

   Function Test

   Actuate the auxiliary valves (yellow, blue, red, green, etc.) via the cab controls to ensure they respond normally and no longer lock themselves in the neutral position.