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 fuel pump is mounted to the gear housing. The fuel pump actuator is mounted on the fuel pump. The fuel pressure sensor is mounted in the high pressure fuel rail. The fuel pressure relief valve is mounted on the high pressure fuel rail.

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

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the fuel pressure relief valve had opened at a pressure lower than expected.

Action Taken When the Fault Code is ActiveThe ECM logs the fault code immediately when the diagnostic runs and fails.Conditions for Clearing the Fault CodeThe fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after 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 applications.

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