Massey Ferguson 3509.31 – Engine Control Unit (ECU): Engine Module 5 Volt Sensor Supply Voltage Issue

The Engine Electronic Management (EEM4) monitoring system has detected an internal failure or an out-of-range voltage on the 5-volt sensor supply circuit 1. This condition is typically caused by a short circuit within one of the sensors powered by this specific 5V circuit, a short in the wiring harness, or an internal hardware failure 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
• 5710 SL
• 5711 SL
• 5712 SL
• 5713 SL

1. 1

   Disconnect sensors on the 5Vdc Supply 1 circuit (such as the engine oil pressure sensor) one by one to isolate internal sensor shorts. If the 5V supply voltage returns to normal or the fault code becomes inactive, the unplugged sensor is shorted.

2. 2

   Inspect the engine wiring harness for chafing, pinched wires, or exposed copper that could cause a short to ground or a short to voltage along the 5V reference circuit.

3. 3

   Verify ECU integrity by checking if the 5V supply remains out of range after all sensors are unplugged and the harness tests good for continuity and isolation.

1. 1

   Power Down

   Turn the ignition switch to OFF and wait at least 2 minutes for the ECU to power down completely and save its data.

2. 2

   Test Voltage

   Turn the key ON (engine OFF). Use a multimeter to measure the voltage at the disconnected sensor harness connector. It should read approximately 5.0 volts.

3. 3

   Repair Wiring/Sensor

   If a sensor is found to be internally shorted during the diagnostic checks, replace the sensor, clear the codes, and verify the repair. If the harness is damaged, repair the wiring.

4. 4

   ECU Replacement

   If deemed faulty: Connect the AGCO Electronic Diagnostic Tool (EDT). Save the engine log information and the injector IQA calibration codes. Select 'Engine ECU Replacement' in the configuration menu and follow the prompts to deactivate the old EEM4 unit. Turn the ignition OFF, wait 2 minutes, and physically swap the ECU. Turn the ignition ON. The EDT will read the serial number of the new EEM4 unit. Follow the software prompts to activate and calibrate the new unit.