Cummins ISB4.5 CM2150 Fault Code: 272 PID: SPN: 1347 FMI: 3 Engine Fuel Pump Pressurizing Assembly 1 Circuit – Voltage Above Normal or Shorted to High Source.

Description

Circuit Description
The circuit is a pulse width modulation (PWM) driver in the electronic control module (ECM) that controls the fuel pump actuator. The actuator is grounded in the ECM. The actuator is normally open. The PWM duty cycle to the fuel pump actuator depends on the difference between desired rail pressure and sensed rail pressure.

Component Location
The fuel pump actuator is located on the engine-mounted fuel pump housing. The engine wiring harness and the ECM are other components in the circuit that can cause this fault code.

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

Conditions for Setting the Fault Codes
The fuel pump actuator circuit PWM signal is detected to be greater than 0-VDC when the PWM signal is turned off by the ECM.

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.
-Fuel rail pressure will be higher than the commanded rail pressure.

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 immediately after the diagnostic runs and passes. To validate the repair, start the engine and let it idle for 1 minute.
-The ECM 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.

Shop Talk
This fault becomes active when the ECM detects an open in the fuel pump actuator circuit. Causes of this fault code are a short circuit to positive voltage or an open circuit in the fuel pump actuator circuit. If there is high harness resistance or an intermittent open circuit, Fault Code 2311 can have high inactive counts. If the fault code is intermittent, look closely for causes of an intermittent open circuit such as loose pins, bad connections, or loose wire connections at the ECM connector. Also, if the fault code is intermittent, wiggle the harness while monitoring the fault code state to check for a wiring issue internal to the harness.