Volvo SPN 3226 FMI 12 (Bad NOx Sensor)

Mounted on passenger frame rail with 8" wire that leads to sensor end that threads into scr catalyst. It is about 1/2 way back roughly under where passenger seat is. Type it into ebay to see what it looks like. 2 10mm bolts hold it to frame. 1 1/16" wrench (I think) to unscrew sensor end from can. Pretty expensive from dealer. Cheap on ebay.

 

Does not have to be calibrated. Do not wait too long because truck will not regen if sensor is not working properly. After changing, do a regen.

 

It is very common, and you should replace the sensors in pairs (inlet and outlet) at the same time. Problem is, as you found out, they are very expensive sensors. I hope that you kept the old inlet sensor as a spare. I think that your readings are not serious, but maybe Nasriza will chime in. He is really good with Volvo's. I am O.K.

 

Good to hear.

 

When you had this problem, what was happening to your truck aside from not doing its regen? Does it affect engine performance?

I've had my 2012 for almost a year now and I'm getting an error for the NOX outlet sensor for about 10 months and it seems like it's doing its regen and I've been refueling DEF. The truck runs good.