Cummins ISB4.5 CM2150 Fault Code: 386 PID: SID 212 SPN: 3509 FMI: 3 Sensor Supply 1 Circuit – Voltage Above Normal or Shorted to High Source.

Circuit Description
The sensor supply 1 of the electronic control module (ECM) provides a 5 volt supply for the barometric pressure sensor, fuel rail pressure sensor, intake manifold temperature/pressure combination sensor, and camshaft speed/position sensor.

Component Location
Sensor supply number 1 is located in the ECM engine harness connector and provides a 5 volt supply to various pressure sensors.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes
The ECM detects that the sensor supply 1 signal voltage is greater than 5.25-VDC for more than 1 second.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE lamp and/or the MIL immediately after the diagnostic runs and fails.
-Engine torque could possibly be reduced.
-A default value is used for all of the sensors on the sensor supply 1 circuit.

Conditions for Clearing the Fault Code
-This fault code can not be cleared with INSITE™ electronic service tool.
-To validate the repair, start the engine and let it idle for 1 minute.
-The ECM will turn off the amber CHECK ENGINE lamp and/or MIL immediately after the diagnostic runs and passes.
-Use INSITE™ electronic service tool to verify the fault code is inactive.
-The inactive fault code will be cleared from the memory after 9600 hours of engine operation without a reoccurrence.

Shop Talk
Low voltage on the 5 volt supply line can be caused by a short circuit to ground in a supply line, a short circuit between a supply line and a return line, a malfunctioning sensor, or a malfunctioning ECM power supply.