Massey Ferguson 3.02.95 – TECU (Tractor Electronic Control Unit): High Voltage On Auxiliary Valve Switch 6 (TECU)

The control module has detected that the voltage signal returning from the Auxiliary Valve Switch 6 (typically a fingertip proportional switch on the armrest or joystick) is exceeding the maximum expected threshold. This almost always indicates a short circuit to power (12V) in the wiring harness, a failed internal potentiometer/contact inside the switch, or moisture ingress causing a short.

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

1. 1

   Visual Inspection: Inspect the armrest console and the specific fingertip switch (Switch 6) for physical damage, sticking, or liquid spills (a common cause of armrest switch shorts).

2. 2

   Harness Testing: Disconnect the switch. Use a digital multimeter to measure the signal wire going back to the TECU. If it reads 12V while disconnected, the wiring harness is shorted to a power wire somewhere between the armrest and the TECU.

3. 3

   Switch Testing: Check the resistance/continuity of the switch itself. If it shows a dead short across the signal and power pins regardless of switch position, the switch has failed internally.

4. 4

   Reference Voltage Check: Verify that the TECU is supplying the correct reference voltage (usually 5V or 10V) to the switch. (Note: Code AR 01 indicates an issue with the 10V supply from the TECU, which can sometimes trigger secondary switch faults).

1. 1

   Power Down

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

2. 2

   Access the Switch

   Carefully pry up or unscrew the armrest control console cover to expose the underside of the fingertip joystick/switch modules.

3. 3

   Disconnect

   Unplug the electrical connector specifically routed to Auxiliary Valve Switch 6.

4. 4

   Replace

   If the switch was deemed faulty during diagnostics, unclip or unscrew the switch module from the armrest housing and install the replacement OEM switch.

5. 5

   Reassemble & Power Up

   Reconnect the wiring harness, secure the armrest console, and reconnect the battery.

6. 6

   Calibrate

   Turn the key to the ON position. You must clear the inactive 3.02.95 fault code. Note: Installing a new switch will often trigger a secondary code (03.X.96 - Calibration Issue For Valve Switch 6). You will need to use the tractor's dashboard diagnostic menu or a dealer service tool to run the auxiliary valve calibration routine so the TECU can learn the new switch's minimum and maximum voltage values.