Cummins ISB4.5 CM2150 Fault Code: 553 PID: 157 SPN: 157 FMI: 16 Injector Metering Rail 1 Pressure – Data Valid But Above Normal Operating Range – Moderately Severe Level.

Circuit Description
The engine control module (ECM) monitors engine operating conditions, including the reading of rail fuel pressure, and changes the flow command to either increase (Open the fuel pump actuator) or decrease (Close the fuel pump actuator) the fuel supply to the high-pressure pump.

Component Location
The fuel pump actuator is installed in the adapter on the back of the high-pressure fuel pump.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes
The ECM has detected that the fuel rail pressure reading has exceeded the recommended operating limits.

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.

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.
-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
A fuel pump actuator with excessive leakage or a damaged inboard o-ring will result in high fuel rail pressures at idle or light load.

If the fuel pump actuator exhibits excessive leakage, it is possible that the fuel rail pressure will reach the opening pressure of the fuel rail pressure relief valve and Fault Code 1911 could possibly become active.

The fuel rail pressure sensor can also be checked. When checking the fuel rail pressure sensor accuracy, make sure the high-pressure fuel rail is not pressurized. The fuel pump, high-pressure fuel lines, and fuel rail contain very high-pressure fuel. Do not loosen any fittings while the engine is running. Wait at least 10 minutes after shutting down the engine before loosening any fittings in the high-pressure fuel system to allow pressure to decrease to a lower level. There could be a significant amount of time waiting on the rail to depressurize to zero on some engines. In such cases, it could be necessary to manually relieve the pressure from the high-pressure fuel rail.