Cummins ISB4.5 CM2150 Fault Code: 176 PID: SID 254 SPN: 3464 FMI: 4 Electronic Throttle Control Actuator Driver Circuit – Voltage Below Normal or Shorted to Low Source.

Circuit Description
The engine control module (ECM) controls the engine intake throttle actuator, opening and closing it based on various operating conditions. The engine intake throttle actuator is opened and closed by a DC motor that receives voltage from the ECM on the engine intake throttle actuator motor signal (+) and (-) circuits. To open the valve, the motor receives voltage on the engine intake throttle actuator motor signal (+) circuit. To close the valve, the motor receives voltage on the exhaust gas recirculation (EGR) valve motor signal (-) circuit.

Component Location
The engine intake throttle actuator is mounted in the intake air stream, between the charge air cooler and intake manifold.

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

Conditions for Setting the Fault Codes
The ECM detects a short circuit to ground in the engine intake throttle actuator motor supply circuit.

Action Taken When the Fault Code is Active
-The ECM illuminates the red STOP ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails. The intake throttle actuator operation will be disabled, and the valve will default to the open position.

Conditions for Clearing the Fault Code
-The fault code will always be inactive at key ON. To validate the repair, start and idle the engine for 1 minute. If the fault code does not become active again, the repair has been validated.
-The ECM will turn off the MIL after three consecutive ignition cycles that the diagnostic runs and passes.
-This fault code can also be cleared with the INSITE™ electronic service tool.

Shop Talk
The ECM monitors the voltage level of the circuit and logs a fault code if the voltage level indicates a short to ground. This fault is always set inactive when the keyswitch is turned ON. If there is a malfunction of this circuit, the fault code will not be set active until the actuator has been actuated. For these reasons, this troubleshooting tree must be used for both active and inactive fault codes.

Possible causes of this fault is intake throttle actuator motor output (+ or -) leads shorted to ground in the harness, intake throttle actuator motor, or ECM.

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