Cummins ISX11.9 CM2250 (2010-12) Fault Code: 2638 (X) PID: SID 380 SPN: 5298 FMI: 17 Aftertreatment Diesel oxidation Catalyst Conversion Efficiency- Data Valid But Below Normal Operating range- Least Severe Level

Circuit Description
The aftertreatment system is monitored by three temperature sensors that are located in the exhaust system. The aftertreatment intake temperature sensor is located after the turbocharger outlet, at the intake of the aftertreatment system. The aftertreatment DPF intake temperature sensor is located between the aftertreatment DOC and the aftertreatment DPF. The aftertreatment DPF outlet temperature sensor is located after the aftertreatment DPF. The temperature sensors around the aftertreatment DOC are used to monitor the temperature differential across the catalyst during active regeneration of the aftertreatment system.

Component Location
The aftertreatment DOC is located in the exhaust system. The location of the catalyst can vary, depending on the original equipment manufacturer (OEM). Refer to the OEM service manual.

Conditions for Running the Diagnostics
Active regeneration of the aftertreatment DPF must be occurring before the diagnostic will function.
Conditions for Setting the Fault Codes
The engine control module (ECM) detects that the temperature differential across the aftertreatment DOC during active regeneration is not matching the expected temperature increase.

Action Taken When the Fault Code is Active
The ECM logs the fault code immediately when the diagnostic runs and fails on two consecutive trips.
The exhaust gas recirculation (EGR) valve operation will be disabled.
Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
Conditions for Clearing the Fault Code
The fault code will be set to inactive after performing INSITE? electronic service tool Aftertreatment DPF regeneration test, and the DOC efficiency is determined to be above a calibratible threshold.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
For On-Board Diagnostics (OBD) engines, the ECM will turn off the malfunction indicator lamp (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.

Shop Talk
This fault code is logged when the conversion efficiency of the DOC is calculated to be less than that required to perform an effective regeneration.

Possible causes of this fault code include:

Soot plugging the front face of the aftertreatment DOC
Engine oil or fuel contamination of the aftertreatment DOC
A cracked or contaminated aftertreatment DOC
A damaged aftertreatment fuel injection system
A leaking exhaust system between the turbocharger and the DOC.
An in-range malfunction of the aftertreatment DOC or the aftertreatment DPF inlet temperature sensor can cause this fault code. Make sure there are not any fault codes related to the aftertreatment temperature sensors before following this troubleshooting tree.

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and data link 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.

Possible Cause:
1) Aftertreatment Injector
2) ECM calibration