Fendt 06.1.05 – Comfort Rear PTO / Rear PTO Enhanced Control (Enhanced Control ECU A002): B021 - Sensor, rear PTO speed (clutch)

Signal fault or faulty Hall-effect speed sensor. The system detects that the actual speed of the PTO stub shaft differs from the specified setpoint speed of the PTO clutch by more than plus/minus 12%. Standard PTO engagement fails, but the PTO can still be engaged in emergency mode by pressing and holding the emergency PTO button for 5 seconds.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III) (409, 410, 411, 412)
• Fendt 700 Vario (COM III) (711, 712, 714, 716)
• Fendt 800 Vario (COM III) (815, 817, 818)
• Fendt 900 Vario (COM III & S4) (916, 919, 920, 922, 924, 926, 927, 930, 933, 936, 939)

1. 1

   Verify the 12V power supply to the sensor by checking Fuse 34 (A013 module).

2. 2

   Inspect the wiring harness and connector for the B021 sensor at separation point X170 for corrosion, chafing, or loose pins.

3. 3

   Check the PTO clutch solenoid valves (Y026, Y027, Y028) for incorrect wiring or mechanical seizing, which can also cause the 12% speed mismatch.

4. 4

   Verify there is no mechanical fault or binding in the PTO speed selector mechanism.

1. 1

   Locate the Sensor

   Locate the B021 Hall-effect speed sensor, which is mounted at the rear PTO clutch assembly.

2. 2

   Disconnect

   Disconnect the wiring harness at separation point X170.

3. 3

   Remove Sensor

   Unbolt and remove the faulty B021 speed sensor from the clutch housing.

4. 4

   Install New Sensor

   Install the replacement OEM Hall-effect sensor.

5. 5

   Reconnect and Clear

   Reconnect the X170 wiring harness plug. Turn on the ignition and clear the stored 06.1.05 fault code from the tractor's memory.

6. 6

   Test Operation

   Engage the rear PTO normally (without using the 5-second emergency override) to confirm the speed mismatch is resolved and the clutch engages smoothly.