Massey Ferguson 3.02.87 – TECU (Tractor Electronic Control Unit) / Armrest Autotronic 5: High Voltage On Auxiliary Valve Switch 3 (TECU)

The system has detected a short circuit to 12V on the circuit for the 3rd auxiliary spool valve control switch (FingerTIP 3 switch). It can also indicate a calibration failure for Valve Switch 3.

• 5713SL
• 5712SL
• 5711SL
• T4
• 5710SL
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726
• 8600 Series

1. 1

   Locate the FingerTIP 3 switch (Auxiliary Valve Switch 3) on the tractor's armrest console

2. 2

   Inspect the wiring harness between the Armrest Autotronic 5 TECU and the FingerTIP 3 switch (connector X108 or X587)

3. 3

   Disconnect the switch and use a multimeter to check the wiring harness for a short to power (12V)

4. 4

   If the harness tests fine, test the internal potentiometer/contacts of the FingerTIP 3 switch itself for a short

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery's negative terminal to prevent further electrical damage.

2. 2

   Access the Armrest

   Carefully disassemble the armrest console to expose the FingerTIP switches and the Armrest Autotronic 5 TECU wiring.

3. 3

   Isolate the Circuit

   Disconnect connector X108 (or X587) from the FingerTIP 3 switch.

4. 4

   Repair Wiring

   If your multimeter tests revealed a short to 12V in the harness (e.g., rubbed wires touching a power source), repair the damaged section of the wiring harness and apply heat-shrink tubing.

5. 5

   Replace the Switch

   If the wiring is intact, the fault is internal to the switch. Remove the retaining hardware for the FingerTIP 3 switch and install a new unit.

6. 6

   Reassemble and Calibrate

   Reconnect the switch, reassemble the armrest, and reconnect the battery. Because this code can also be triggered by a calibration issue, you must use the tractor's terminal or a dealer diagnostic tool (like the AGCO EDT) to recalibrate the auxiliary valve switches before operating the machine.