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AdBlue Alert

Posted: Tue Oct 14, 2025 9:20 am
by Jacob_Evans2001
I have the following codes shown and a message on the dashboard indicating a countdown till the vehicle will fail to start.
Diagnostic codes P2BAE-00, P2BAE-02, and P229E-14.
I have depleted the old AdBlue and replenished the tank with 8 litres of new fluid.

Verified that the line from the tank to the injector is unobstructed.
Inspected the injector from the exhaust.
Prepared and subjected the line to pressure testing using a diagnostic equipment.
Recalibrated the pump using a diagnostic scan tool.
Inspected the cabling from the NOx sensor to the connector adjacent to the fuse box.
Verified the data line from the NOx sensor, measuring 60 ohms.
Verified the supplied voltage to the NOx connector and conducted a load test.
I connected the CAN bus High and Low to an oscilloscope and obtained a clear trace for both CanH and CanL.
Unable to clear the codes and reset the countdown or quality monitor using the scan tool, as it fails consistently.
I am somewhat perplexed. Regrettably, I am unable to interpret the NOx result using the scan tool, as it is not supported; hence, I cannot ascertain whether I have elevated NOx emissions or if the sensor is malfunctioning.
Has anyone experienced the same issue? Your assistance would be greatly appreciated, as it is causing me considerable frustration.

Re: AdBlue Alert

Posted: Tue Oct 14, 2025 9:21 am
by James_Rover99
Your tests indicate a defective NOx sensor. You have eliminated nearly all other possibilities. The system detects elevated NOx levels, initiating the countdown, with a faulty sensor being the predominant cause. Despite optimal CAN signalling, the sensor may nonetheless transmit erroneous data.

A new NOx sensor will likely be required to resolve this issue. This is a recognised failure spot in numerous contemporary diesel engines.

Re: AdBlue Alert

Posted: Tue Oct 14, 2025 9:21 am
by Jacob_Evans2001
Revision. Reattached a new NOx sensor end to the old model and conducted a test drive. After around 10 to 15 minutes, the dashboard alert disappeared. Subsequently, I was able to reset the problem codes. I observed that a faulty sensor causes the EGR to overcompensate, resulting in diminished power below 2000 RPM.
Currently, everything appears satisfactory; hence, I am hopeful that this condition persists for some time.
Thank you

Re: AdBlue Alert

Posted: Tue Oct 14, 2025 9:22 am
by James_Rover99
It is good to learn that you have resolved the issue. A defective NOx sensor is a typical indication that disrupts the EGR, resulting in diminished low-end output. Well done on resolving the issue. I hope it remains resolved for you.

Re: AdBlue Alert

Posted: Tue Oct 14, 2025 9:22 am
by Jacob_Evans2001
I appreciate your response.
I want to take it to my local mechanic on Monday for them to assess the exhaust and determine the exact NOx levels.
I have a question regarding the P229E-14 code. The 14 at the conclusion is indicated as a short or open circuit. Do you know if this pertains to the incoming supply voltage to the sensor or the CAN twisted pair? Could it be located within the sensor head?

Re: AdBlue Alert

Posted: Tue Oct 14, 2025 9:22 am
by James_Rover99
The -14 value often indicates an internal failure of the sensor. It is a prevalent site of failure. The garage can verify this; nonetheless, it is probable that a new sensor will be required.