Massey Ferguson 04.01.71 – Transmission Control Unit (TRANS / TCU): Cruise Speed C2 Button Issue (TRANS)

The system has detected an irregular, missing, or implausible electrical signal coming from the "C2" cruise control button. The C2 button is typically located on the tractor's multifunction joystick or armrest and is used by the operator to set or engage the secondary constant forward cruise speed.

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

1. 1

   Physical Inspection: Inspect the C2 button on the multifunction joystick. Check if the button is physically stuck, depressed, or lacks the normal tactile "click" when pressed. Agricultural dust and debris often jam these microswitches.

2. 2

   Wiring & Connector Check: Trace the wiring harness from the base of the multifunction joystick/armrest down to the Transmission ECU. Look for pinched wires, chafing, or loose connector pins.

3. 3

   Continuity Testing: Using a digital multimeter, test the C2 switch for continuity. It should show an open circuit when released and a closed circuit (low resistance) when pressed. If it reads closed constantly, the switch is shorted/stuck.

4. 4

   Moisture Check: Check the joystick housing for signs of moisture or liquid ingress, which can short the switch contacts.

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical spikes during repair.

2. 2

   Disassemble the Joystick/Armrest

   Carefully remove the retaining screws on the multifunction joystick handle or the armrest control pod to access the internal switch wiring.

3. 3

   Remove the Faulty Switch

   Disconnect the micro-connector attaching the C2 button to the joystick's internal circuit board.

4. 4

   Replace the Component

   Depending on the exact joystick revision, you will either snap a new C2 microswitch into the housing or, if the button is integrated into a sealed circuit board, replace the upper joystick handle assembly.

5. 5

   Reassembly

   Reconnect the switch wiring, ensuring the wires are routed cleanly so they will not be pinched when the joystick halves are put back together. Secure the housing screws.

6. 6

   Test and Clear Codes

   Reconnect the battery. Turn the ignition on and test the C2 button's physical movement. Use the tractor's SIS (System Information Screen) or a dealer diagnostic tool to clear the 04.01.71 fault code. Test drive the tractor to ensure the C2 cruise speed engages properly.