Volvo All Engines (2010 Emissions) Fault Code: SPN 4094 FMI 18 PID: PSID 90 Nox Limits Exceeded Due to Insufficient Reagent Quality

This function indicates that the NOx conversion efficiency is not correct

Conditions for diagnostic trouble code (DTC):
1) Too high NOx emissions

Observable symptoms
1) Possible engine de-rate

Probable cause
1) Charge air system
2) EGR Mass Flow
3) Diluted, wrong or contaminated Aftertreatment Diesel Exhaust Fluid (DEF) in Aftertreatment diesel exhaust fluid (DEF) tank
4) Aftertreatment Hydrocarbon Doser, over-fueling
5) Fuel Injection System Over-Fueling
6) Aftertreatment selective catalytic reduction (SCR) system Dosing too low
7) Insufficient Aftertreatment Diesel Exhaust Fluid (DEF) supply to Aftertreatment Diesel Exhaust Fluid (DEF) Pump
8) SCR Catalyst