Massey Ferguson AR31 – TECU (Tractor Electronic Control Unit): High Amp Draw On Auxiliary Valve Switch 3 (TECU)
Issue description
The controller is detecting a short to ground on the electrical circuit for the 3rd auxiliary hydraulic valve control switch located on the armrest.
Applies to these machines
33 machines- 7616
- 5612
- 7622
- Interim Tier 4 (2012-2015)
- 7614
- 5611
- 7615
- 5610
- 5613
- 7620
- 5609
- 7618
- 5608
- 7619
- 7626
- 7624
- 8600 Series
- 8670
- 8690
- 7600 Series
- 7700 Series
- 7714
- 7715
- 7716
- 7718
- 7719
- 7720
- 7722
- 7724
- 7726
- 5600 Series
- 4700 Series
- 5700SL Series
Check the cause
Verify the active error code number on the instrument panel to confirm AR31 is present.
Inspect the wiring harness between the Armrest Autotronic 5 module (X104) and the FingerTIP 3 switch (Connector X587 or X108) for pinched wires, chafing, or moisture.
Use a multimeter to test for a short to ground (0V) on the signal wire leading to the switch.
Disconnect the switch to see if the short to ground goes away. If the short disappears when unplugged, the switch has failed internally.
Repair steps
Disconnect battery
Disconnect the tractor's battery to prevent electrical damage during repair.
Disassemble armrest console
Disassemble the armrest console to access the underside of the FingerTIP switch bank.
Disconnect switch
Locate the FingerTIP 3 switch (Connector X587 or X108) and disconnect it from the wiring harness.
Repair harness or remove switch
If the diagnostic tests pointed to a wiring issue, repair the shorted section of the armrest harness. If the switch is faulty, remove the retaining hardware and extract the FingerTIP 3 switch.
Install new switch
Install the new FingerTIP 3 switch and reconnect the harness.
Reassemble and reconnect
Reassemble the armrest console and reconnect the battery.
Calibrate switch
Turn on the tractor and clear the fault codes. You must perform a calibration procedure for the new switch. Failure to calibrate the new switch will trigger a related fault code, AR39.
Parts you might need
(1)FingerTIP 3 Switch / Auxiliary Valve Control Switch
Ensure you are replacing the switch in the 3rd position. Only use genuine Massey Ferguson replacement parts. Specific 8-digit AGCO part numbers vary heavily based on the exact tractor model, year, and armrest configuration; technicians must look up the exact switch in the AGCO parts catalog using the tractor's specific serial number.
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