Error Code P20EE on Peugeot 308 T9 (2016) – NOx Sensor & SCR System.
Hi everyone,
I’m having an issue with my Peugeot 308 T9 (2016). The car is showing fault code P20EE, which is related to the NOx sensor and the SCR (AdBlue) system.
Here’s what I’ve done so far:
Checked the AdBlue tank and replaced a faulty thermistor with a 10 kΩ unit because one sensor was reading 0 °C.
In August last year, I replaced the NOx sensor head but kept the original electronic module. After that, everything worked fine until now.
Despite these fixes, the same error P20EE has come back.
Current readings:
At engine idle, the NOx sensor shows around 150 ppm, and occasionally up to 200 ppm.
I’ve read in several forums that this issue can sometimes be solved by cleaning the NOx sensor and the injector head.
Has anyone tried this? Do you know if monitoring the NOx sensor readings (ppm) can help diagnose the problem?
Additional question:
Using DIAGBOX, what parameters can be checked to confirm that both the catalytic converter and the DPF are functioning correctly? For example, differential pressure across the DPF, soot load, regeneration status, SCR efficiency, or any other relevant values.
Any advice or experience would be greatly appreciated!
Thanks in advance!
AI: Are there any other fault codes present alongside P20EE, or is this the only one showing up in DIAGBOX?
yes
AI: Have you noticed any issues with AdBlue consumption, recent refills, or warning messages on the dashboard related to AdBlue or emissions?
no
