Massey Ferguson 3361.11 – Engine Control Unit (ECU) / Engine Module: DEF Injector Has Not Opened Or Closed As Expected

A mechanical or flow-related failure within the Selective Catalytic Reduction (SCR) system where the Diesel Exhaust Fluid (DEF) dosing injector is either stuck open (often due to crystal deposits holding it off-seat) or stuck closed (due to a fully blocked nozzle or electrical failure). When this occurs, the system cannot properly meter DEF into the exhaust stream to reduce NOx emissions, which will eventually force the tractor into a derate or 'limp' mode.

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

1. 1

   Visually inspect the DEF injector nozzle and surrounding exhaust port for white, crusty urea crystal deposits.

2. 2

   Check for electrical continuity at the injector's connector and inspect the wiring harness and pins for corrosion, damage, or wear.

3. 3

   Perform a bidirectional scan tool test by commanding the DEF injector open and monitoring exhaust backpressure or downstream NOx readings (no change indicates no flow).

4. 4

   Measure the flow rate by removing the injector (leaving lines connected), commanding it to fire into a graduated cylinder for a set duration, and comparing the output to manufacturer specifications.

1. 1

   Preparation

   Ensure the engine is turned off and the exhaust system is completely cool to prevent burns. Disconnect the battery to eliminate electrical risks.

2. 2

   Removal

   Disconnect the electrical harness connector from the DEF injector. Carefully disconnect the DEF fluid line, capping the line immediately to prevent dirt or debris from contaminating the system.

3. 3

   Dismounting

   Remove the mounting nuts, screws, or V-band clamp securing the DEF injector to the exhaust SCR catalyst. Pull the injector straight out.

4. 4

   Cleaning (If Salvageable)

   If the injector is heavily crystallized but electrically sound, clean the nozzle using an appropriate DEF system cleaning fluid or warm distilled water to dissolve the urea deposits. Do not use harsh abrasives on the nozzle tip.

5. 5

   Replacement

   If cleaning is ineffective or the injector has failed electrically, prepare the new OEM injector.

6. 6

   Installation

   Install the new (or cleaned) DEF injector into the exhaust port. Crucial: Always use a new doser/injector gasket (or V-band clamp + gasket) to prevent exhaust leaks.

7. 7

   Reconnection

   Torque the mounting hardware to manufacturer specifications. Reconnect the DEF fluid line and the electrical harness.

8. 8

   Filter Maintenance

   It is highly recommended to replace the DEF pump filter/strainer at this time to prevent downstream contamination from clogging the new injector.

9. 9

   Finalization

   Reconnect the battery, clear the fault codes using a diagnostic scanner, and run the tractor to verify proper SCR operation and ensure there are no leaks.