Cummins ISB4.5 CM2150 Fault Code: 3539 PID: SPN: 51 FMI: 3 Engine Intake Throttle Actuator Position Sensor Circuit – Voltage Above Normal or Shorted to High Source.

Circuit Description
The engine control module uses the engine intake throttle actuator position sensor to determine whether or not the actuator is meeting the commanded position. The engine control module supplies 5 Volts to the engine intake throttle actuator position signal circuit, and the engine throttle actuator position sensor outputs a voltage signal to the engine control module based on the actuator position. The engine control module converts this signal into a percentage value, 0 to 100, indicating actuator position. A fully open actuator is equivalent to 100 percent.

Component Location
The engine throttle actuator position sensor is internal to the engine throttle actuator assembly and can not be serviced separately.

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 engine control module detects that the engine throttle actuator position sensor signal voltage is greater than a calibratible value.

Action Taken When the Fault Code is Active
-The engine control module illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
-Engine intake throttle actuator operation will be disabled, and the intake throttle actuator will be opened.

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 intake throttle actuator will perform an auto-zero immediately after key-on.
-The engine control module will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
-The engine control module will turn off the MIL after three consecutive ignition cycles that the diagnostic runs and passes.
-This fault code and MIL can also be cleared with INSITE™ electronic service tool.

Possible Causes
-Open return in the harness, connectors, or sensor
-SIGNAL wire shorted to sensor supply
-Malfunctioning intake throttle actuator position sensor
-Malfunctioning engine control module.

NOTE: Do not supply 12-VDC the intake throttle actuator position sensor, or short the intake throttle actuator motor wires to the intake throttle actuator position sensor. The intake throttle actuator position sensor and at 5-VDC, and sensor damage can occur.