Cummins ISX12 CM2250 (2010-12) Fault Code: 2646 PID: 110 SPN: 110 FMI: 31 Engine Coolant Temperature- Condition Exists

Circuit Description
When the engine coolant temperature nears the engine protection limits, the exhaust gas recirculation (EGR) valve will be closed to reduce the coolant temperature. This fault code is used as an information fault code, only indicating that the EGR valve has closed.

Component Location
The engine coolant temperature sensor is located on the thermostat housing.

Conditions for Running the Diagnostics
This diagnostic runs continuously when engine speed is greater than 500 rpm.

Conditions for Setting the Fault Codes
The fault code is set active when the EGR valve is closed to reduce engine coolant temperature.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
Conditions for Clearing the Fault Code
To validate the repair, perform a key cycle, and leave the key in the ON position for 1 minute.
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.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
When the engine coolant temperature nears the engine protection limits, the EGR valve will be closed to reduce the coolant temperature. This fault code is used as an information fault code, only indicating that the EGR valve has closed. No malfunction has occurred to cause this fault code. Other engine protection fault codes will be active if the engine coolant temperature has exceeded the engine protection limits.

Possible Cause:
1) ECM calibration