Fendt 04.1.05 – Transmission Control System: B039 - High pressure sensor II (push detection) - Signal fault / Sensor faulty

The sensor monitoring the secondary high-pressure circuit in the Vario transmission is sending an implausible signal, has failed, or has lost its power supply. This causes the TMS to switch off, limits engine power to 70%, and disables the active parking/hold function.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• 300 Vario series (309, 310, 311, 312)
• 400 Vario series
• 700 Vario series
• 800 Vario series
• 900 Vario series (916 through 936)

1. 1

   Check the power supply and fuses on the A013 module (Fuse 31 for 12V systems, or Fuse 15 for 8.5V systems)

2. 2

   Inspect the wiring harness leading to the B039 sensor for chafing, breaks, or corrosion at the connector, paying special attention to separation point X177

3. 3

   Check the valve block area for hydraulic leaks that may have damaged the sensor connector

1. 1

   Locate the Sensor

   The B039 high-pressure sensor 2 is located on the right side of the Vario transmission, mounted directly on the transmission valve block.

2. 2

   Gain Access

   Safely lift and support the tractor. You must remove the right rear wheel and the inner metal shielding panels to access the valve block.

3. 3

   Remove the Sensor

   Disconnect the electrical harness from the B039 sensor. Carefully unscrew the sensor from the hydraulic manifold port. Have a catch pan ready, as a small amount of hydraulic fluid may escape.

4. 4

   Install the New Sensor

   The sensor seals with an O-ring. Ensure the old O-ring is removed and install the new sensor with a fresh O-ring. Thread it into the port and tighten to OEM torque specifications.

5. 5

   Reassembly

   Reconnect the electrical harness. Reinstall the metal panels and the right rear wheel.

6. 6

   Clear and Test

   Clear the fault codes from the transmission ECU. Test drive the tractor to ensure the TMS engages properly and the active hold/parking function is restored.