Fendt 5.1.33 – Comfort Hydraulics module (A050 Basic Control Unit ECU / Transmission E-box A002): 4WD clutch solenoid valve — Actuation fault

The 4WD function is terminated, and the system defaults to a fail-safe state where the 4WD engages automatically.

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• 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
• Farmer 400 series
• Favorit 700 and 900 series
• 300, 400, 700, 800, 900, and 1000 Vario series (including COM III generations)

1. 1

   Inspect the wiring harness and electrical connector leading to the Y009 4WD clutch solenoid valve for chafing, corrosion, or loose pins

2. 2

   Test the solenoid circuit for an actuation fault, checking for an open circuit, a short to ground, or a short to power

3. 3

   Verify there are no accompanying CAN bus faults (e.g., between A004 and A002) that might be interrupting the signal to the solenoid

1. 1

   Locate the Solenoid

   Locate the Y009 4WD clutch solenoid valve on the transmission/hydraulic valve block.

2. 2

   Disconnect and Verify

   Disconnect the electrical harness. If the wiring tests fine but the solenoid fails a resistance test (or is mechanically sticking), the valve must be replaced.

3. 3

   Replacement

   Remove the mounting bolts securing the solenoid. When installing the new genuine replacement, ensure the O-ring is replaced and lubricated, and torque the mounting bolts to factory specifications to preserve factory response timing and prevent pressure loss.

4. 4

   Clear Fault Codes

   To clear the fault from the instrument panel (A007), call up the fault code on the terminal and press the designated confirmation buttons (often the A, B, and C / both arrow keys simultaneously). Note: Faults stored deep in the A050 Basic Control Unit ECU may require FENDIAS diagnostic software to be permanently cleared from the memory.