Fendt 4.1.66 – Transmission Control Unit: Relay faulty, solenoid valve faulty, or signal transmission (signal line) faulty

Indicates a failure in the active parking function (active hold function). The tractor will have no active parking/hold function, and the engine brake stationary control is disabled.

• 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
• Fendt 300 Vario (COM III)
• Fendt 400 Vario / Farmer 400 (including COM III)
• Fendt 700 Vario / Favorit 700 (including COM III)
• Fendt 800 Vario (including COM III)
• Fendt 900 Vario / Favorit 900 (including COM III)

1. 1

   Check Relay K051 (located in the fuse/relay box at the right rear of the cab) to see if it is functioning properly.

2. 2

   Check Solenoid Valve Y053 actuation for faults on both the earth (ground) side and the positive (+) side.

3. 3

   Inspect the wiring harness and signal lines between the Transmission ECU, the K051 relay, and the Y053 solenoid valve for continuity, shorts to ground, or broken wires.

1. 1

   Access the Relay Panel

   Locate the K051 relay (usually at the right rear in the cab, under the cover).

2. 2

   Test/Replace Relay K051

   Remove the relay and test continuity across pins 3 and 5 when energized. If the relay fails to click, or if pins 3 and 5 are stuck closed/open, replace the K051 relay.

3. 3

   Inspect Wiring

   If the relay is good, use a multimeter to trace the signal line from the relay panel to the Y053 solenoid valve (located on the transmission/rear axle cardan brake area). Repair any damaged wiring.

4. 4

   Test/Replace Solenoid Valve Y053

   If the wiring and relay are intact, test the Y053 solenoid valve's resistance and verify it receives voltage when the active hold function is commanded. If the solenoid is internally shorted or open, relieve hydraulic pressure safely, remove the faulty Y053 solenoid valve, and install a replacement.

5. 5

   Clear Codes

   Clear the stored fault codes from the tractor's memory using the terminal and test drive the tractor to ensure the active parking function engages properly.