Cummins ISB4.5 CM2150 Fault Code: 187 PID: SID 211 SPN: 3510 FMI: 4 Sensor Supply 2 Circuit – Voltage Below Normal or Shorted to Low Source.

Circuit Description
The sensor supply number 2 pin of the electronic control module (ECM) provides (+) 5-VDC for the camshaft position sensor, exhaust gas pressure sensor, rail fuel pressure sensor, intake manifold pressure/temperature sensor, and crankcase pressure sensor.

Component Location
Sensor supply number 2 is located in the ECM and provides a 5-VDC 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 operating.

Conditions for Setting the Fault Codes
The ECM detects that the sensor supply 2 signal voltage is less than a calibratible value for more than 1 second.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE light and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
-A default value is used for the intake manifold pressure sensor.
-The backup camshaft position sensor will not be functional.

Conditions for Clearing the Fault Code
The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.

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.