Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 6462 PID: SPN: 3226 FMI: 2/20 Aftertreatment 1 Outlet NOx Sensor – Data Not Rational – Drifted High

Lamp:
None

Reason:
An offset in the outlet NOx sensor reading has been detected.

Effect:
None on performance.

Circuit Description:
The aftertreatment outlet NOx (nitrogen oxides) sensor is a smart device and communicates with the Engine Control Module (ECM) via the J1939 data link. The aftertreatment outlet NOx sensor performs its own internal diagnostics and reports malfunctions back to the primary ECM using the J1939 data link. The NOx sensor is permanently attached to the NOx control module. They are serviced as a single component and can not be replaced individually. The aftertreatment outlet NOx sensor is used to measure the NOx emissions at the outlet of the aftertreatment system.

Component Location:
The aftertreatment outlet NOx sensor location can vary depending on engine application. It is usually located in the exhaust system at the outlet of the Selective Catalytic Reduction (SCR) catalyst.

Conditions for Running the Diagnostics:
This diagnostic runs when the aftertreatment SCR outlet temperature is above 200°C [392°F], and the engine is in a motoring condition.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the aftertreatment outlet NOx sensor was not reading zero while in a motoring (non-fueling) condition.

Action Taken When the Fault Code is Active:
The ECM illuminates the amber check engine lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.

Conditions for Clearing the Fault Code:
1. 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 the diagnostic tool.
2. The aftertreatment SCR outlet temperature must be above 200°C [392°F] for 60 seconds before the aftertreatment outlet NOx sensor can run its internal diagnostics.
3. The fault code status displayed by the diagnostic tool will change to inactive immediately after the diagnostic runs and passes.
4. The ECM will turn off the amber check engine lamp immediately after the diagnostic runs and passes.
5. For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
6. The reset all faults command in the diagnostic tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
Possible causes of this fault code include:
1. Malfunctioning aftertreatment outlet NOx sensor.
2. Diesel exhaust fluid crystallization or deposits.
3. Improperly installed aftertreatment outlet NOx sensor.
4. Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.
5. For intermittent power supply and datalink communication issues with aftertreatment components, it is highly recommended that the OEM power distribution center fuses and relays be thoroughly checked for loose, missing or intermittent connections.