SPN 4334 is a diagnostic trouble code for Aftertreatment 1 Diesel Exhaust Fluid Doser.
FMI 2 – Absolute Pressure Data Erratic, Intermittent Or Incorrect
FMI 3 – Absolute Pressure Voltage Above Normal, Or Shorted To High Source
FMI 4 – Absolute Pressure Voltage Below Normal, Or Shorted To Low Source
FMI 16 – Absolute Pressure Data Valid But Above Normal Operating Range – Moderately Severe
FMI 18 – Absolute Pressure Data Valid But Below Normal Operating Range – Moderately Severe
Troubleshoot:
DEF sensor
