Massey Ferguson 3510.31 – Engine Control Unit (ECU): Engine Module 5 Volt Sensor Supply Voltage Issue / 5Vdc Supply 2 voltage out of range.

The engine management monitoring system has detected an internal failure or an out-of-range voltage on the 5V sensor supply circuit 2. This is almost always caused by a short circuit to ground within one of the 3-wire engine sensors powered by this specific circuit, a short in the wiring harness, or a defective internal power supply within the ECU itself.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724

1. 1

   Clear and Retest: Save the error log, erase it, and restart the ECU. If the fault returns immediately during the next driving cycle, a hard short is present.

2. 2

   Sensor Isolation Test: Disconnect the engine sensors powered by the 5V Supply 2 circuit one at a time (typically 3-wire pressure sensors like oil pressure, boost pressure, rail pressure, or throttle position).

3. 3

   Monitor Voltage: With the key ON (engine off), monitor the active fault codes or measure the voltage at the 5V pin of the disconnected connector. If the 5V reference returns to normal, the sensor you just unplugged is internally shorted.

4. 4

   Harness Inspection: If all sensors are unplugged and the 5V supply is still out of range, use a multimeter to check the 5V supply wire in the harness for continuity to ground (chafing, pinched wires).

5. 5

   ECU Pin Check: Check the ECU connectors for oxidation, moisture, or bent pins.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the battery negative cable before inspecting the ECU harness to prevent electrical spikes.

2. 2

   Isolate the Short

   Perform the sensor isolation test described above.

3. 3

   Replace Faulty Sensor

   If unplugging a specific sensor restores the 5V circuit, replace that sensor. Do not attempt to repair a shorted sensor.

4. 4

   Repair Wiring

   If the harness is shorted to the engine block or chassis, open the wire loom, locate the chafed wire, splice in a new section using weather-sealed heat shrink connectors, and re-loom the harness securely away from vibration points.

5. 5

   Test the ECU

   If no short circuit is found in the sensors or the wiring harness, the internal power stage of the ECU is defective. Test the system with a known good EEM4 controller. If the system is functional with the replacement ECU, the original ECU must be replaced and flashed with the correct machine software by a dealer.

6. 6

   Clear Codes

   Reconnect all components, turn the key ON, clear the inactive fault codes, and test run the tractor to verify the repair.