Fendt 4.1.05 – TRANSMISSION control unit: High pressure sensor II (push detection) — Signal fault

The transmission control system is receiving an invalid signal or no signal from the secondary high-pressure sensor (B039). This is typically caused by a faulty sensor, a wiring issue (signal fault), or a loss of supply voltage.

• 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
• 300 Vario
• 309
• 310
• 311
• 312
• 400 Vario
• 411
• 412
• 700 Vario
• 711
• 712
• 714
• 716
• 800 Vario
• 815
• 817
• 818
• 900 Vario
• 916
• 920
• 924
• 926
• 930
• 936

1. 1

   Check the supply voltage fuse (e.g., fuse A013, 2, 3, 15, or 31 depending on the specific Vario model and generation)

2. 2

   Test the connector at the sensor to ensure it is receiving the correct supply voltage (either 8.5 VDC or 12 VDC)

3. 3

   Inspect the wiring harness and separation point connector (X177) for breaks, short circuits, corrosion, or loose pins

4. 4

   Test the sensor signal voltage and current draw with the engine running above 1400 rpm (expected values range from 0.80 VDC / 4.0 mADC at 0 bar to 3.00 VDC / 14.8 mADC at 400 bar)

1. 1

   Locate the Sensor

   The B039 High Pressure Sensor II is located on the right side of the transmission, on the valve block.

2. 2

   Gain Access

   To access the valve block, remove the right rear wheel and the right-side metal shielding panels.

3. 3

   Disconnect

   Disconnect the electrical connector (separation point X177) from the B039 sensor.

4. 4

   Remove and Replace

   Unscrew the faulty sensor from the transmission valve block. Install the new sensor and tighten it to the manufacturer's torque specification.

5. 5

   Reassemble

   Reconnect the X177 electrical connector, reinstall the metal panels, and remount the right rear wheel.

6. 6

   Calibrate

   Clear the fault codes from the terminal and carry out a systematic transmission calibration.