Fendt A.1.69 – A057 - ECU, Steering Controller (Autoguide): Y087 - Steering valve block, Autoguide: Supply voltage > 32 V.

An overvoltage condition where the electrical supply to the Autoguide steering valve block has exceeded 32 volts, usually pointing to a severe charging system malfunction (like a failed alternator voltage regulator) or a major short-to-power in the wiring harness.

• 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 700 Vario (COM III)
• FENDT 800 Vario (COM III)
• FENDT 900 Vario (COM III)

1. 1

   Test the alternator output at the battery with a multimeter while the engine is running to check for an overcharging condition (>32V)

2. 2

   Inspect the electrical supply line to the steering valve for shorts to a higher voltage source (consult Fendt wiring diagram Sheet 39)

3. 3

   Inspect the connector at the Y087 steering valve block for corrosion, water ingress, or damaged pins that could be bridging circuits

1. 1

   Disconnect Power

   Disconnect the tractor's batteries before performing any electrical repairs to prevent further damage.

2. 2

   Resolve Overvoltage Source

   If the alternator voltage regulator has failed and is outputting >32V, replace the alternator/regulator assembly.

3. 3

   Repair Wiring

   If the alternator is fine, locate and repair the short-to-power in the wiring harness leading to the Y087 valve block (referencing Sheet 39).

4. 4

   Replace the Valve Block

   If the overvoltage condition burned out the internal sensors or solenoids of the steering valve block, the Y087 unit must be replaced.

5. 5

   Clear Codes

   Reconnect the batteries, turn the key on, and clear the stored fault codes from the terminal.

6. 6

   Recalibrate the System

   If the steering valve block was replaced or disconnected, perform system calibrations via the terminal: Run Calibration Code 2403 (VarioGuide steering valve calibration) and Calibration Code 2401 (Steering angle sensor calibration).