Technical NOx Sensor Issues

[Leanneschmeanne]

Hi I’ve got a 19 plate Fiat Tipo and I’m having no end of problems with it!
One day the Check Engine light and Stop Start Unavailable light came on without warning and wouldn’t be budged even though car is running fine, no limp mode or sluggishness.
Put it on diagnostic and code P221300, P229F00 and P222400 came up and I was told I needed a new NOx sensor which I bought.
Had it replaced and the car worked back to normal for literally one day before all the same lights and error codes came back on. No garage seems to know what is causing it and are even suggesting a new ECU which I don’t want to pay!
Has anyone else had this issue?

 

[Barkydog]

I would check the battery condition. When they are faulty they can cause many strange warning lights etc. I had a battery with a bad cell and it threw up all sorts of warnings when there was nothing wrong. Various lights from brake radar, airbag, traction control etc etc. New battery problems never came back

 

[FirstTimeFiatDriver]

Without being 100% sure, I have heard from car mechanics that Lambda sensors is better to get replaced in pairs, because the aged sensor can still trigger errors. The reason according to them is that there is a gap between the readings of the old and the new sensor and that difference causes Error codes, even if its sensor on its own works within its expected range.