Massey Ferguson 4.X.16 – Transmission Controller: Transmission Module Low Supply Voltage (TRANS)

The supply voltage (+APC) to the transmission controller has dropped too low, specifically falling below 7 Volts.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 5400 Series
• 6400 Series
• 5600 Series
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5700SL Series
• 7700 Series
• 7700S Series
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 4700 Global Series
• 6700 Global Series

1. 1

   Verify that the tractor's battery is fully charged and that the alternator is outputting the correct voltage (typically 13.5V - 14.5V). A weak system voltage will trigger this code.

2. 2

   Locate the transmission controller power supply relays. Test the neutral relay (often designated as relay #16) and relay #15. Test for voltage between relay #15 cavity 3 and relay #16 cavity 5 for a short to power. If no voltage is present, the neutral relay (#16) has likely failed.

3. 3

   Check the wiring harness and connectors leading to the transmission controller for corrosion, chafing, or loose pins that could cause a severe voltage drop (+APC < 7V).

4. 4

   Inspect all fuses related to the transmission controller and cab power supply.

1. 1

   Disconnect Power

   Disconnect the negative battery terminal before beginning any electrical work.

2. 2

   Access the Relays

   Locate the fuse and relay panel (usually on the right-hand console or under the dashboard, depending on the model).

3. 3

   Replace Faulty Relays

   Based on the diagnostic test, if relay #16 (neutral relay) or the main transmission power relay has failed or shows high resistance, replace it with a new OEM relay.

4. 4

   Repair Wiring

   If the relays test fine, trace the power supply wire (+APC) from the relay panel to the transmission controller. Clean any corroded connector pins with electrical contact cleaner and repair any damaged wiring.

5. 5

   Module Replacement (Worst Case)

   If the wiring harness delivers full battery voltage to the controller plug, but the controller still logs an internal low voltage fault and fails to operate, the transmission controller itself has an internal short and must be replaced.

6. 6

   Reassembly and Testing

   Reconnect the battery, turn the ignition on, and clear the fault codes. Start the tractor and test the transmission through all ranges to ensure the voltage remains stable and the code does not return.