We just purchased a 2012 cascadia with a dd15. We're brand new to this whole def thing. Can anyone tell me what these codes mean. Spn 520702 fmi 4 Spn 523531 fmi 31 Spn 2567 fmi 0 Spn 4335 fmi 1 Your response is greatly appreciated
You might want a look into getting code reader software, It's not that expensive and can be extremely informative.
520702 is a light, not sure which one, maybe in cab, maybe outside 523531same as above. If all your lights are working then ignore these two. 2567 is a cluster communication error. no big deal, check cluster harness in back of the cluster. 4335 fmi 1 is the bad one Diesel Exhaust Fluid (DEF) Air Pressure Not Detected (From Vehicle Supply). 25% Derate. Could be DEF Metering unit, pressure sensor, pump See attached diags.
