Fendt 4.1.53 – Transmission Control Module (Transmission TCU): Transmission oil temperature has exceeded 110°C (230°F)

A critical thermal event triggered by the B009 Thermo switch indicating the transmission oil temperature has exceeded 110°C (230°F). Continuing to drive the tractor in this condition will cause severe damage to the Vario transmission.

• 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
• Fendt 300 Vario series (COM III)
• Fendt 400 Vario series (COM III)
• Fendt 700 and 800 Vario series (COM III)
• Fendt 900 Vario series (COM III)
• Older Favorit and Farmer series tractors
• 818 Vario
• 820 Vario
• Farmer 300 series
• Favorit 611-615 series

1. 1

   Verify operational load (heavy tractive work in speed range II, excessive clutch pedal actuation, or prolonged turbo clutch function)

2. 2

   Inspect the transmission oil cooler and radiator for dirt, chaff, or blockages restricting airflow

3. 3

   Check transmission oil level (overfilled or low) and condition (smell for burnt or acrid odor indicating loss of viscosity)

4. 4

   Check electrical grounds, specifically battery connections and the cab ground disconnect above the batteries

5. 5

   Inspect the wiring harness leading to the B009 thermo switch for shorts, breaks, or signal line faults

1. 1

   Halt Operation

   Stop the tractor immediately to prevent internal transmission damage.

2. 2

   Adjust Driving Habits

   If the overheating was caused by heavy draft work in range II, switch the transmission to speed range I. If the turbo clutch was active too long, increase engine speed over 1400 rpm to assist cooling.

3. 3

   Clean the Cooler

   Thoroughly blow out and clean the transmission oil cooler and surrounding radiator fins.

4. 4

   Correct Fluid Levels

   Adjust the transmission oil level. If you do a lot of roading, some technicians recommend running the oil level at the bottom mark of the dipstick/sight glass to prevent heating. If the oil smells burnt, drain and replace the transmission oil and the high-pressure hydraulic filters immediately.

5. 5

   Clean Electrical Grounds

   Disconnect, wire-brush, and re-secure the main battery cables and cab ground straps.

6. 6

   Replace the Sensor

   If the transmission is physically cool but the terminal still displays the 4.1.53 fault, the B009 thermo switch has likely failed. Locate the sensor on the transmission housing, disconnect the harness, unthread the old sensor, and install the replacement.

7. 7

   Clear Codes

   Turn the ignition OFF and ON (Reset) and use the Variotronic terminal (using the 'ESC' key to accept faults) to clear the warning messages.