Cummins ISB4.5 CM2150 Fault Code: 2371 PID: SPN: 1074 FMI: 3 Engine (Exhaust) Brake Driver Circuit – Voltage Above Normal or Shorted to High Source.

Circuit Description
The exhaust brake is used to retard engine speed by creating high exhaust back pressure, subsequently slowing the vehicle down and extending the life of the service brakes. This back pressure is obtained by restricting airflow through the exhaust system with a butterfly valve.

Component Location
The exhaust brake is located in the exhaust stream, after the turbocharger outlet.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes
The ECM detects that the voltage in the exhaust brake control circuit is above a calibratible value.

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, start the engine and let it idle for 1 minute.
-The ECM will turn off the amber CHECK ENGINE light and the fault code will go inactive immediately after the diagnostic runs and passes.
-This fault code can also be cleared with INSITE™ electronic service tool.

Possible Causes
-Open circuit in the engine harness or exhaust brake actuator
-Short to voltage source in the engine harness
-Malfunctioning ECM.