Cummins ISX12 CM2250 (2010-12) Fault Code: 272 PID: SPN: 272 FMI: 3 Engine Fuel Pump Pressurizing Assembly 1 Circuit- Voltage Above Normal or Shorted to High Source

Circuit Description
The circuit is a pulse-width modulation (PWM) driver in the engine 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 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 ECM has detected a short to battery, short pin-to-pin, or open circuit in the fuel pump actuator circuit.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp 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.
Active and stationary regeneration of the diesel particulate filter will be disabled.
The exhaust gas recirculation (EGR) valve will be closed.
Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
Conditions for Clearing the Fault Code
To validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop-and-go city driving and steady-state highway driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.
To validate the repair using a Chassis Dynamometer Test, utilize a routine that incorporates acceleration and motoring events, steady-state highway operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
For On-Board Diagnostic (OBD) engines, the ECM will turn off the MIL after three consecutive trips where the diagnostic runs and passes.
The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD engines.

Shop Talk
This fault becomes active when the ECM detects an open or short circuit in the fuel pump actuator circuit. Causes of this fault code include a short circuit to a positive voltage, open circuit, short circuit to ground, or low resistance (fuel pump actuator is shorted internally) 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. When excessive current or a short circuit is detected, the ECM driver to the fuel pump actuator is turned off to protect the circuit. It is necessary to cycle the keyswitch OFF and then back ON before the ECM will run this diagnostic again. The ECM driver is enabled at key ON, so if the cause is no longer present, the fault code will become inactive and can be cleared.

If the fault code is intermittent, inspect the ECM connector, wiring harness, and harness connectors for loose pins and bad connections. Look closely for loose wire connections that can cause an intermittent short to ground or open circuit in the wiring harness or connectors. It may help to wiggle the harness and harness connections and watch for fault code state changes.

Possible Cause:
1) N/A