Massey Ferguson 06.01.05 – TRANS1: Issue With Rear PTO Clutch Speed Sensor Signal Dyna VT

The transmission controller is not receiving a valid, plausible speed signal from the rear PTO clutch speed sensor (B021). The signal may be out of range, short-circuited to ground, or completely missing. When this fault is active, the PTO clutch disc pack may fail to separate properly, the PTO brake may become non-operational, and the tractor will default to an emergency/limp mode for the PTO system.

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 6614
• 6615
• 6616
• 6713 S
• 6714 S
• 6715 S
• 6716 S
• 6718 S
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8727 S
• 8730 S
• 8732 S
• 8735 S
• 8737 S
• 8740 S

1. 1

   Locate the rear PTO clutch speed sensor (B021) at the rear of the tractor, mounted on the rear axle cover or PTO housing.

2. 2

   Visually inspect the sensor's wiring harness and 3-pin connector for physical damage, corrosion, or loose pins, paying special attention to wire chafing near the rear axle.

3. 3

   Test the 3-pin Hall-effect sensor electrically (Pin 1 = Earth, Pin 2 = +Supply, Pin 3 = Signal). Verify the TRANS1 ECU is sending a ~6.3 VDC basic signal voltage.

4. 4

   Check for continuity on the signal wire back to the ECU and ensure it is not short-circuited to ground.

5. 5

   Connect a diagnostic PC (AGCO EDT or FENDIAS) to monitor the live PTO speed signal. If wiring tests good but the sensor reads 0 RPM or erratic spikes while the PTO is engaged, the sensor has failed internally.

1. 1

   Prepare tractor

   Park the tractor on a level surface, turn off the engine, remove the key, and engage the parking brake.

2. 2

   Locate sensor

   Locate the B021 Rear PTO Clutch Speed Sensor at the rear of the transmission/axle housing. You may need to remove a protective panel to access it.

3. 3

   Clean area

   Thoroughly clean the area around the sensor to prevent dirt from falling into the transmission housing.

4. 4

   Disconnect connector

   Disconnect the 3-pin electrical connector from the sensor.

5. 5

   Remove bolt

   Remove the retaining bolt securing the sensor.

6. 6

   Remove sensor

   Carefully pull the old sensor out of the housing. Have a shop rag ready, as a small amount of transmission/hydraulic oil may seep out.

7. 7

   Lubricate O-ring

   Lubricate the O-ring on the new sensor with clean transmission oil to prevent tearing during installation.

8. 8

   Install new sensor

   Insert the new sensor into the housing and secure it with the retaining bolt.

9. 9

   Reconnect connector

   Reconnect the electrical connector, ensuring it clicks into place.

10. 10

    Clear fault code

    Turn the ignition on and use your diagnostic tool to clear the 06.01.05 fault code.

11. 11

    Verify repair

    Start the tractor, engage the PTO, and verify that the fault does not return and the PTO operates smoothly.