Fendt 4.1.56 – Transmission Control Unit (TCU): "Transmission oil filter clogged" switch — Signal fault

This code indicates an electrical signal failure (such as an open circuit, short to ground, or short to power) in the circuit for the S017 transmission oil filter contamination switch.

• 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
• Farmer 400 Vario
• Favorit 700 and 900 Vario
• Fendt 300, 400, 700, 800, and 900 Vario series (including COM III and S4 generations)

1. 1

   Warm Up the Tractor: Bring the transmission oil temperature above 50°C to ensure the TCU is actively monitoring the circuit.

2. 2

   Visual Inspection: Locate the S017 switch on the transmission oil filter housing. Inspect the electrical connector and wiring harness for visible damage, chafing, or heavy corrosion.

3. 3

   Circuit Testing: Use a multimeter to check the signal line between the S017 switch and the Transmission Control module for continuity. Test for a short to ground or a short to voltage.

4. 4

   Switch Testing: Test the S017 switch itself for internal electrical failure (plausibility error).

1. 1

   Clean the Area

   Thoroughly clean the area around the transmission oil filter housing and the S017 switch to prevent dirt from entering the hydraulic system.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a broken wire or corroded connector pin in the signal line, repair the harness and replace the connector terminal.

3. 3

   Replace the Switch

   If the wiring is intact, the S017 switch has failed internally. Disconnect the electrical harness, unscrew the faulty S017 switch from the filter housing, and install the new OEM switch.

4. 4

   Replace the Filter

   While working on the filter housing, it is highly recommended to replace the transmission oil filter and its O-rings, especially if the tractor is near its service interval (typically every 1,000 to 1,500 hours).

5. 5

   Clear Codes and Test

   Clear the fault codes from the tractor's terminal. Operate the tractor under load until the transmission oil temperature exceeds 50°C to verify the signal fault does not return.