DESCRIPTION:This fault code sets when the Aftertreatment Control Module (ACM) detects that the NOx conversion is lower than a calibrated threshold.

MONITORED PARAMETER:1. Selective Catalyst Reduction (SCR) inlet NOx sensor.2. SCR outlet NOx sensor.

TYPICAL ENABLING CONDITIONS:1. Diesel Exhaust Fluid (DEF) dosing enabled.2. 1000 – 1500 rpm.3. 15 – 100% load.4. SCR inlet temperature sensor less than 650°C (1200°F).5. Ambient temperature greater than 0°C (32°F).6. Coolant temperature greater than 70°C (158°F).7. Non-regeneration conditions present.

MONITOR SEQUENCE:None

EXECUTION FREQUENCY:Continuous when enabling conditions met.

TYPICAL DURATION:30 minutes

DASH LAMPS:MIL

ENGINE REACTION:Derate 25%

VERIFICATION:Parked regeneration

NOTE: If any 3364-xx codes present, fix those first.

PROBABLE CAUSES:1. DEF tank contaminated (fuel, water, etc…).2. DEF pressure sensor failure.3. DEF pressure sensor connector/harness.4. Perform stationary regen.5. DEF air supply lines cracked/leaked/kinked.