Circuit DescriptionThe high-pressure relief valve is a mechanical device that opens when the fuel pressure in the fuel rail exceeds a critical warning limit.

Component LocationThe high-pressure relief valve is located on the fuel rail.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the engine is operating.

Conditions for Setting the Fault CodesThe ECM has detected that the fuel pressure relief valve has opened at a pressure lower than expected.

Action Taken When the Fault Code is ActiveThis is a no lamp fault, which will be set in conjunction with Fault Code 1911. The ECM will illuminate the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) for Fault Code 1911.Conditions for Clearing the Fault CodeThe fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately following each key cycle or when the relief valve is able to reset itself and the diagnostic runs and passes.The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop TalkThis fault code will become inactive at each key OFF event, and will not become active again until the fault condition reoccurs. Troubleshoot inactive or active occurences of this fault code the same.

An occurence of this fault indicates that the high-pressure relief valve is being tripped at a pressure lower than what is expected. If this has happened multiple times, there will be many occurences of this fault. Troubleshoot Fault Code 3727 before Fault Code 1911, if both fault codes are present in the ECM.

This fault code may also be triggered by a sudden and significant loss of fuel pressure in the fuel system.

Possible Cause:1) ECM calibration