Massey Ferguson 03.01.8A – TECU: High Amp Draw On Auxiliary Valve Switch 4 (TECU)

The control module is detecting an excessive current draw on the circuit belonging to the switch that operates the 4th auxiliary (spool) valve. This is typically caused by a short circuit to 0 V (a short to ground) either within the wiring harness or an internal short inside the switch itself.

• 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
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Visually inspect the wiring harness routing from the armrest console (Auxiliary Valve Switch 4) down to the TECU for pinched wires, chafed insulation, or rubbing against the chassis

2. 2

   Disconnect the switch and inspect the connector pins for moisture, corrosion, or bent pins

3. 3

   Isolate the switch by disconnecting it and turning the key ON; if the fault code changes to a high voltage or open circuit code, the switch is internally shorted

4. 4

   Perform a harness continuity test using a multimeter to check the signal wire from the switch connector to the TECU for continuity to ground

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 necessary trim panels on the armrest console to access the underside of the fingertip auxiliary valve switches.

3. 3

   Remove the Faulty Component

   Unplug the electrical connector for Auxiliary Valve Switch 4. Depress the retaining tabs or remove the mounting screws holding the switch in the console bezel, and pull the switch out.

4. 4

   Repair Wiring

   If the diagnostic checks pointed to a harness short, locate the chafed section of the wire. Cut out the damaged section, solder in a new piece of wire of the same gauge, and seal it with marine-grade heat shrink tubing.

5. 5

   Install New Switch

   Push the new auxiliary valve switch into the console until it clicks into place. Reconnect the electrical plug.

6. 6

   Reassemble and Test

   Reinstall the armrest trim panels. Reconnect the battery. Turn the ignition ON, clear the stored fault codes via the dash or diagnostic tool, and actuate Auxiliary Valve 4 to ensure the code does not return and the hydraulic spool responds correctly.