CODE REASON EFFECT
Fault Code: 3748
Aftertreatment Intake NOx Sensor - Data Not Rational - Drifted High. An offset in the intake NOx sensor reading has been detected.
Conditions for Clearing the Fault Code
To validate the repair, start and operate the engine to raise exhaust temperatures. This can be done by either driving the vehicle or initiating a stationary regeneration using INSITE™ electronic service tool.
The DOC intake temperature at the aftertreatment intake NOx sensor must be above 200°C [392°F] before the sensor can perform its internal diagnostics.
The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn OFF the amber CHECK ENGINE lamp after the diagnostic runs and passes.
For On-Board Diagnostics (OBD) engines, the ECM will turn OFF the MIL after three consecutive trips where the diagnostic runs and passes.
The "Reset All Faults" command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.
Possible causes of this fault code include:
Malfunctioning aftertreatment intake NOx sensor
Improperly installed aftertreatment intake NOx sensor.
Installation of the sensor:
Apply a light coating of anti-seize compound to the threads of the NOx sensor.
torque to 37 ftlbs
Install the NOx sensor in to the after-treatment adapter pipe and tighten the retaining nut.
Be sure that the NOx sensor is connected to the engine wiring harness.
Be sure that the orientation of the small module is with the engine wiring harness connection located at the bottom of the sensor.
Be sure that the small module is secured to the application by the two mounting capscrews.
NOTE: The NOx sensor wire connection must not be pulled tight. Damage to the sensor can occur