Cummins CM850/CM2850 Engine Fault Code 2311 Low Power Error Solution

Cummins CM850 and CM2850 engine fault code 2311,Electronic Fuel Injection Control Valve Circuit - Condition Exists. Fuel pump actuator circuit resistance too high or too low.

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Circuit Description
The circuit is a pulse width modulation (PWM) driver in the ECM that controls the fuel pump pressurizing assembly 1. The fuel pump pressurizing assembly 1 is grounded in the ECM. The ECM varies the current to this valve to provide the correct fuel flow to the high-pressure pump based on engine operating conditions. The fuel pump pressurizing assembly 1 valve is a normally open valve. High circuit resistance can cause fuel pressure to be higher than commanded at light loads and Fault Code 1911 can be logged.

 

Component Location
The fuel pump pressurizing assembly 1 valve is located on the engine mounted fuel pump housing.

Use the following procedur for a detailed component location view. Refer to Procedure 100-002 in Section E.
 

Shop Talk
If this fault code occurs during road test, verify that all connectors are clean and free of corrosion before replacing components. This fault code can become active for any of the following reasons: Fuel pump pressurizing assembly 1 high resistance
Engine harness high resistance
Loose, worn, or corroded connectors or pins
Fuel pump pressurizing assembly 1 with low internal resistance
Fuel pump pressurizing assembly 1 or engine harness that has shorted to ground
Intermittent circuit failures that cause the fuel pressure to exceed the fuel rail pressure relief valve opening pressure.

If an intermittent electrical circuit problem of the fuel pump pressurizing assembly 1 circuit exists, it is possible for the fault code to become active then inactive during normal engine operation. For example, if a poor connection causes an intermittent open or short circuit, the normally open valve will open in a fraction of a second, while the circuit is faulty causing the fuel rail pressure relief valve to open. Following the event that caused the fuel rail pressure relief valve to open, the ECM will attempt to reset the fuel rail pressure relief valve, provided the fuel pump pressurizing assembly 1 circuit is not still failed.

Following any event that opens the fuel rail pressure relief valve, the fuel rail pressure relief valve will regulate the fuel pressure at approximately 900 bar [13,053 psi]. If the ECM is still capable of controlling fuel pressure, the following will occur: The measured fuel pressure will reduce to 600 bar [8702 psi] as the ECM prepares to seat the fuel rail pressure relief valve.
Once pressure is 600 bar [8702 psi] and engine speed is greater than 1200 rpm, the ECM will momentarily close the fuel pump pressurizing assembly 1. This action will reduce the fuel rail pressure (to less than 20 bar [290 psi] for a fraction of a second) so that the fuel rail pressure relief valve will reset. At light engine loads, especially if the engine is sped while the driveline is not engaged, engine power interruption will be noticeable while the ECM attempts to reset the fuel rail pressure relief valve.
Once the ECM detects that the fuel rail pressure relief valve is reset, normal engine operation will resume and Fault Code 2311 will become inactive.
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