Massey Ferguson 04.02.2A – Transmission Controller (TRANS): Transmission Output Speed Sensor Issue

This code is triggered when the controller detects an erratic, missing, or implausible signal from the transmission output speed sensor (also referred to as the theoretical forward speed sensor or shaft speed sensor).

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 7700 Series
• 5400 Series
• 6400 Series
• 6600 Series
• 6700 Series
• 7600 Series

1. 1

   Connect the Wintest diagnostic tool and monitor the transmission output speed parameter to check if any speed is detected while the tractor is moving.

2. 2

   Perform a resistance test with the ignition off and the sensor disconnected. Measure the resistance across the sensor's two pins (should be 450 Ohms ± 20 Ohms at room temperature).

3. 3

   Check for an alternating voltage (AC) signal from the sensor when the ring gear is rotating.

4. 4

   Inspect the wiring harness and connectors between the sensor and the TRANS controller for open circuits, shorts to ground, or backed-out pins.

1. 1

   Locate the Sensor

   The sensor is typically threaded into the transmission housing above the differential ring gear.

2. 2

   Remove the Old Sensor

   Disconnect the wiring harness, loosen the counter-nut, and unscrew the faulty sensor. (Note: Depending on the fluid level, you may need to partially drain the transmission oil).

3. 3

   Prepare the New Sensor

   Apply a small amount of thread sealant (OEM recommends Loctite 5922) to the threads of the new sensor.

4. 4

   Set the Air Gap

   Manually screw the new sensor in fully until it bottoms out against the gear. Carefully unscrew the sensor by exactly ¾ of a turn to establish the correct air gap.

5. 5

   Secure the Sensor

   Tighten the counter-nut to approximately 6 Nm.

6. 6

   Finalize

   Reconnect the wiring harness, top off any lost transmission fluid, clear the fault codes, and test drive the tractor to verify the speed signal is restored.