2016 Volvo Check Engine Fault P225C00

This is a potentially “deep” fault code. P225C indicates an issue at your inlet NOx sensor. The scr system has inlet and outlet Nox sensors that monitor the efficiency of the scr system. This fault does not necessarily indicate a fault with the sensor (although it is possible), but flags that the Nox reading is too high in the exhaust gas entering the scr portion of the aftertreatment. It’s impossible for me to tell you what to change but I’ll give you some potentials...
At a dealer, the first step it to perform a “Nox conversion” test. The dealer will likely tell you that you need to replace the inlet Nox sensor to proceed with further diag ($600). They will then perform another Nox conversion. Best case scenario, the problem is fixed. If the high Nox fault remains, the issue is now with what the engine is kicking out the pipe. This would likely be an egr problem (flow sensor or plugged egr cooler). Egr is designed to recirculate burnt gas to lower cylinder temps to limit Nox leaving the engine. This is only really the tip of the iceberg. There are a number of other things that can cause the high Nox at the inlet to the scr. My best advice is that when the dealer asks to replace the inlet Nox sensor, ask them if they’d be willing to remove it if it doesn’t fix the problem. Save a few $ at least.

 

Soon. With conversion not happening correctly in the scr, the unit will derate.

 

listen2all, can you share what did it end up being?

 

Hi I’m ahmed i hive morning
check engine fault volvo 2015 780

 

It could be e NOx sensor if the code won’t go away