P0094
CIRCUIT DESCRIPTIONThe Engine Control Module (ECM) uses the Fuel Rail Pressure (FRP) sensor to determine fuel pressure to the fuel injectors. This is then compared to the calculated target fuel pressure as determined by the ECM. The ECM adjusts the fuel rail pressure by modulating the duty cycle of the control driver of the fuel pressure regulator. Injector pulse duration is determined by the measured rail pressure and the target injection fuel into each cylinder. If a sensor circuit malfunction is detected, or the commanded fuel injection pump flow is not within the proper range for a given engine load and speed, Diagnostic Trouble Codes (DTCs) will be set.
CONDITIONS FOR RUNNING THE DTC
^ DTC P0192, P0193, or P1635 are not set.
^ The ignition is ON.
CONDITIONS FOR SETTING THE DTC
The difference between fuel rail pressure sensor and commanded fuel injection pump flow is more than 30 MPa.
ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.
DIAGNOSTIC AIDS
If you have to prime the fuel system, check for the following conditions:
^ A restricted fuel supply line.
^ A fuel supply line air leak.
Refer to Fuel System Diagnosis. Component Tests and General Diagnostics
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