DESCRIPTION:
Selective Catalyst Reduction (SCR) inlet NOx sensor – Drift (Low Box).

MONITORED PARAMETER:
Engine out NOx.

TYPICAL ENABLING CONDITIONS:
1. EGR Mass Flow greater than .08 kg/s.
2. Engine Speed 1450-1900 rpm.
3. Engine Torque 1400-2100 N·m.
4. Battery Voltage greater than 11 vDC .
5. Coolant Temperature greater than 65°C (149°F).
6. Ambient Temperature greater than -8°C (18°F) Ambient.
7. Barometric Pressure greater than 755 mbar.
8. Engine not in regeneration mode.

MONITOR SEQUENCE:
None

EXECUTION FREQUENCY:
Always enabled

TYPICAL DURATION:
1.2 seconds

DASH LAMPS:
MIL

ENGINE REACTION:
None

VERIFICATION:
1. Warm up engine such that coolant temperature greater than 65°C (149°F).
2. Ensure engine is not in regeneration mode.
3. Ensure ambient temperature greater than -8°C (18°F) barometric pressure greater than 755 mbar.

NOTE: If any other EGR codes are active, fix those first.

PROBABLE CAUSES:
1. Inspect the entire air inlet system, charge air cooler, and EGR piping/hoses.
2. Check for failed injector.
3. Check the aftertreatment system for leaks/damage.
4. Perform a high idle regeneration.