New Holland ENG 3528 – Engine Control Unit (ECU) / EDC7: NOx Sensor Plausibility failure - Signal not plausible

The Engine Control Unit (ECU) is receiving a signal from the Nitrogen Oxide (NOx) sensor that does not make logical sense when compared to other engine operating parameters. This indicates the sensor element is failing, degraded, or providing erratic data, or it can be triggered by exhaust leaks or wiring issues.

• T6 Series (T6.120, T6.140, T6.150, T6.160, T6.175)
• T7 Series (T7.170, T7.200, T7.270)
• T8 Series (T8.380)
• T9 Series
• D125C
• D150C
• D180C
• LM Series (LM6.32, LM6.35, LM7.35, LM7.42, LM9.35)
• CX Series
• FR Series (FR450, FR500)

1. 1

   Check for related codes (e.g., 3529, 3530, 3533) that indicate a hard electrical or CAN bus communication failure rather than a plausibility issue

2. 2

   Inspect the NOx sensor's 5-pin MCON electrical connector and the wiring harness leading to the EDC for corrosion, chafing, or loose pins

3. 3

   Inspect the exhaust system upstream of the NOx sensor for leaks, which can introduce outside oxygen or alter exhaust flow

4. 4

   Verify DEF/AdBlue quality, as poor quality or contaminated fluid can cause the SCR system to underperform

1. 1

   Locate the Sensor

   Locate the NOx sensor, which is installed in a provided boss on the SCR muffler or on the exhaust end pipe.

2. 2

   Disconnect the Battery

   Turn off the machine and disconnect the battery to prevent electrical spikes.

3. 3

   Disconnect Wiring

   Unplug the 5-pin electrical connector from the NOx sensor control module.

4. 4

   Remove the Sensor

   Carefully unscrew the NOx sensor probe from the exhaust pipe.

5. 5

   Install the New Sensor

   Thread the new NOx sensor into the exhaust boss. Ensure the sensor is mounted in a way that no condensed water can collect inside the protection tube of the sensing element, especially on vertical exhaust pipes.

6. 6

   Route and Connect the Cable

   Mount the attached sensor ECU to its designated location and plug in the 5-pin connector. The cable length between the sensor probe and its module cannot be freely changed, altered, or spliced.

7. 7

   Clear Codes

   Reconnect the battery. Use a diagnostic tool to clear the ENG 3528 fault code.