Massey Ferguson E3361.04 – Engine ECU (EEM4 - AGCO SISU POWER): DEF Injector Voltage Issue

The control module has detected that the voltage on the high side of the Diesel Exhaust Fluid (DEF) dosing valve/injector circuit is below normal or shorted to a ground source (DEF dosing valve high side short circuit).

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

1. 1

   Visual Inspection: Turn the ignition OFF. Disconnect the DEF dosing unit (injector) harness connector. Inspect both the dosing unit connector and the harness connector for signs of damage, bent, spread, broken, pushed out (unseated), or corroded pins.

2. 2

   Harness Routing Check: Inspect the wiring harness between the Engine ECU and the DEF injector for chafing, rubbing, or melted insulation that could be causing the wire to short against the tractor's chassis/ground.

3. 3

   Voltage & Continuity Testing: Use a multimeter to measure the voltage and continuity on the high side of the DEF dosing unit circuit. Check for continuity to ground on the high-side pin to confirm the short.

4. 4

   Component Testing: Measure the internal resistance of the DEF injector coil. If the resistance is out of specification or shows a dead short to its own housing, the internal solenoid of the injector has failed.

1. 1

   Ensure the ignition is OFF and the machine is safely parked.

2. 2

   Repair or replace the affected section of the wiring harness.

   Perform this if the diagnostic checks reveal damaged wiring or a short to ground in the chassis harness.

3. 3

   Replace the DEF injector.

   Perform this if the wiring tests good and the short is isolated internally to the DEF injector.

4. 4

   Thoroughly clean the area around the DEF injector on the exhaust SCR system.

   This prevents dirt or debris from entering the exhaust or DEF lines.

5. 5

   Disconnect the DEF supply/return lines and the electrical connector from the faulty DEF injector.

6. 6

   Remove the mounting hardware and extract the old DEF injector from the exhaust system.

7. 7

   Install the new DEF injector.

   Ensure any O-rings or gaskets are properly seated to prevent exhaust leaks. Torque the mounting hardware to OEM specifications.

8. 8

   Reconnect the DEF lines and the electrical connector.

9. 9

   Turn the ignition ON, connect a diagnostic scan tool, clear the fault codes, and run the engine.

   Verify the repair and ensure there are no DEF fluid leaks.