Massey Ferguson E4090.16 – Engine Control Unit (ECU): NOx Are High In The Exhaust

The Engine Control Unit (ECU) has detected that nitrogen oxide (NOx) levels in the exhaust are higher than expected. This indicates that the Selective Catalytic Reduction (SCR) after-treatment system is not reducing NOx emissions effectively, which may be due to a problem with the engine's combustion process, emissions control system, or DEF injection. This condition will likely trigger a dashboard warning light and potential engine power derating to limp mode.

• 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

   Check for accompanying codes related to DEF system pressure, DEF metering pump faults, urea quality, or DEF pipe heater resistance (e.g., E4332.11, E4342.04).

2. 2

   Verify DEF/AdBlue quality and level to ensure the tank has adequate, uncontaminated fluid.

3. 3

   Check the NOx sensor signal using a diagnostic tool for irregular signals, missing signals, or out-of-range voltage.

4. 4

   Inspect the NOx sensor wiring harness and connectors for rub points, open circuits, or shorts to ground.

1. 1

   Perform a System Regeneration

   If no other hardware faults are present, utilize the tractor's manual regeneration system to allow the SCR system to burn off soot and attempt to normalize emissions.

2. 2

   Address Root Causes

   If accompanying codes point to a DEF dosing issue (like a blocked injector or failed pump), repair those components first.

3. 3

   Replace the NOx Sensor

   If the NOx sensor is determined to be faulty, reading inaccurately, or has failed internally, remove the old sensor from the exhaust stream and install a replacement.

4. 4

   Clear Codes and Test

   Clear the E4090.16 code from the ECU and perform a test run under load to verify that the NOx emissions value returns to permitted levels.