Massey Ferguson 03.00.86 – TECU: High Amp Draw On Auxiliary Valve Switch 3 (TECU)

Short circuit to 0 V (Short to Ground). The controller is detecting that the electrical current on the circuit for the 3rd auxiliary hydraulic valve switch (often a FingerTIP switch on the armrest) is exceeding normal operating parameters because the signal wire is shorted directly to ground.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608-5613
• 5710SL-5713SL
• 6600s
• 6700s
• 7614-7626
• 7714-7726 (and S models)
• 8670
• 8690
• 8700s

1. 1

   Verify the Code: Confirm if the code is active or stored. If it only happens when the switch is pressed, the switch itself is likely the culprit.

2. 2

   Inspect the Switch: Examine the Auxiliary Valve Switch 3 (FingerTIP 3) on the armrest console. Check for physical damage, sticking, or liquid spills (a common cause of internal switch shorts).

3. 3

   Check the Wiring Harness: Inspect the wiring harness running from the armrest console to the TECU. Look specifically at the armrest harness junction (often labeled X464) and the switch connector for pinched wires, chafing against the seat frame, or exposed copper touching the chassis (0V ground).

4. 4

   Multimeter Testing: Disconnect the switch and test the switch pins for internal continuity to ground when in the neutral position.

5. 5

   Multimeter Testing: Test the signal wire on the harness side for continuity to ground. If there is continuity to ground while disconnected from the switch, the harness is shorted.

1. 1

   Disconnect Power

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

2. 2

   Access the Switch

   Remove the retaining screws and the plastic cladding/cover on the armrest control console to expose the underside of the FingerTIP switches.

3. 3

   Isolate the Fault

   Disconnect the electrical connector for Auxiliary Valve Switch 3.

4. 4

   Repair Wiring (If Applicable)

   If your multimeter test showed a short in the harness, trace the wire back through the armrest pivot point (a common wear area) to the TECU. Splice and heat-shrink any damaged wire, or replace the armrest sub-harness if the damage is extensive.

5. 5

   Replace the Switch (If Applicable)

   If the harness is good but the switch is internally shorted, unclip or unbolt the faulty switch from the armrest bracket and install the replacement switch.

6. 6

   Reassembly

   Reconnect the switch harness, ensuring the connector clicks securely into place. Reinstall the armrest cladding.

7. 7

   Clear Codes and Test

   Reconnect the battery. Turn the ignition on, clear the fault codes via the tractor's diagnostic display or an AGCO/Jaltest diagnostic tool, and actuate Auxiliary Valve 3 to ensure the code does not return and the hydraulic spool responds correctly.