SPN 157 - FMI 18 (Fault Code 559)

SPN157 FMI18
Injector Metering Rail 1 Pressure - Data Valid But Below Normal Operating Range - Moderately Severe Level

Front Fueling Actuator Circuit

Fault Code: 559
PID(P), SID(S): P157
SPN: 157
FMI: 1/18
Lamp: Amber

REASON: The ECM has detected that fuel pressure is lower than commanded pressure.

EFFECT: Possibly hard to start or low power. Engine could possibly not start.

Circuit Description:
The engine control module (ECM) supplies voltage to open the fueling actuators for a short length of time. This allows a short pulse of fuel to flow to the injector. The injector then injects this fuel into the cylinder for combustion.

Component Location:
The front fueling actuator is located on the fuel control housing. It is the first actuator from the front of the engine. The fuel control housing is located on the intake side of the engine below the exhaust gas recirculation (EGR) mixer.

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

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) has detected low rail pressure on the front three cylinders.

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.
• 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, perform a key cycle, start the engine and let it idle for 1 minute.
• The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
• The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
• The “Reset All Faults” command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults.

Shop Talk:
Possible causes of this fault code include:
This fault is set active if the Engine Control Module (ECM) estimates that the front bank is receiving insufficient fuel flow.

Read More:
SPN 723 - FMI 7 (Fault Code 731)
SPN 1381 - FMI 18 (Fault Code 583)


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2 Responses to "SPN 157 - FMI 18 (Fault Code 559)"

  1. Kershaw Skytrim 20/20 modelThrowing the SPN 157 FMI 18 loses power changed all fuel filters still throwing the same code?