Massey Ferguson 03.02.9A – TECU: High Amp Draw On Auxiliary Valve Switch 8 (TECU)

The controller is detecting an excessive current draw on the circuit for the 8th auxiliary valve switch, typically denoting a short circuit to ground (0 V).

• 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 running from the TECU to the multi-function joystick/armrest for chafed wires, pinched harnesses, or melted insulation.

2. 2

   Disconnect connectors at the TECU and auxiliary valve switch to inspect pins for corrosion, moisture ingress, or bent/pushed-out pins.

3. 3

   With the battery disconnected, use a multimeter to test the signal wire for Switch 8 for continuity to ground.

4. 4

   Test the auxiliary valve switch itself for an internal short circuit using a multimeter.

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical damage during testing.

2. 2

   Access the Switch

   Remove the necessary trim panels on the armrest or multi-function joystick to access the auxiliary valve switches.

3. 3

   Isolate the Fault

   Disconnect Auxiliary Valve Switch 8. Reconnect the battery and turn the key to the ON position. If the fault code changes from 'High Amp Draw' (Short to Ground) to an open circuit or calibration error, the switch is internally shorted and must be replaced.

4. 4

   Repair Wiring

   If the short to ground persists with the switch disconnected, the fault lies in the wiring harness. Trace the wire back to the TECU, locate the chafed or damaged section, and repair it using OEM-approved wire splicing techniques or replace the affected harness section.

5. 5

   Replace the Switch

   If the switch was the culprit, install the new push-button auxiliary valve switch into the joystick/armrest assembly.

6. 6

   Clear Codes and Calibrate

   Reconnect all components and the battery. Connect a diagnostic tool (such as the AGCO Electronic Diagnostic Tool - EDT) to clear the stored 03.02.9A fault code. You may need to run a calibration routine for the auxiliary valves after replacing the switch or repairing the circuit.

7. 7

   Test Operation

   Start the tractor and operate Auxiliary Valve 8 to ensure the high amp draw code does not return and the hydraulics function properly.