ECD SYSTEM, Diagnostic DTC:P0093/78

DTC Code DTC Name
P0093/78 Fuel System Leak Detected - Large Leak

DESCRIPTION

Refer to the system description Click here.

DTC No. DTC Detection Condition Trouble Area
P0093/78

Fuel leaks in high-pressure areas

(1 trip detection logic)

  • Fuel line between supply pump and common rail

  • Fuel line between common rail and each injector

  • Suction control valve

  • Common rail

  • Injectors

  • Pressure limiter

  • Open or short in EDU circuit (P0200/97 set simultaneously)

  • Open or short in injector circuit

  • EDU (P0200/97 set simultaneously)

  • ECM

Tech Tips


  • DTC P0093/78 is detected when the engine idle for 1 minute and then run it at 2,500 rpm for 30 seconds.

  • If DTC P1229/78 is set, P0093/78 (fuel leaks in high-pressurized areas) may be set simultaneously. This may be due to the extremely high internal fuel pressure in the common rail causing the pressure limiter to open. The ECM may interpret this as a fault and set P0093/78.

  • For more information on the common rail system, refer to the system description Click here.

  • If P0093/78 is present, refer to the "Diagnostics Trouble Codes (DTCs) Table for Common Rail System" Click here.

  • When DTC P0093/78 is set, check the internal fuel pressure of the common rail by entering the following menus on the intelligent tester : Powertrain / Engine / Data List / Fuel Press.

Reference
Engine Speed Fuel Pressure
Idling Approximately 25 to 35 MPa
3,000 rpm (No engine load) Approximately 35 to 55 MPa

MONITOR DESCRIPTION

P0093/78 (Fuel leaks in high-pressure areas) :

This DTC indicates fuel leaks that exist in highly-pressurized areas in the common rail system. The ECM constantly monitors the internal fuel pressure of the common rail after the engine is started. The ECM sets this DTC if the drop in the internal fuel pressure is large when injecting the fuel.

In the common rail system, high-pressure fuel is always supplied to the high-pressure areas including the supply pump, common rail, injectors and piping. The ECM adjusts the suction control valve opening angle to obtain the target internal fuel pressure

If this DTC is set, the ECM enters fail-safe mode. The fail-safe mode suspends both fuel injection and supply pump operation, and then stops the engine. Before stopping the engine, the ECM permits the vehicle to be driven for 1 minute. The fail-safe mode continues until the ignition switch is turned OFF.

MONITOR STRATEGY

Required sensors Fuel Pressure sensor
Frequency of operation Continuous
Duration 1 second
MIL operation 1 driving cycle

TYPICAL ENABLING CONDITIONS

Item Specification Specification
Minimum Maximum
Engine speed 600 rpm -
The monitor will not run if the fuel pressure sensor or suction control valve circuit is malfunctioning.

TYPICAL MALFUNCTION THRESHOLDS

Threshold
Large drop in the internal fuel pressure when injecting fuel

INSPECTION PROCEDURE

Note

After replaceing the injector, the ECM needs registration Click here.

Tech Tips

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, and other data from the time the malfunction occurred.

When using intelligent tester:

PROCEDURE


  1. CHECK OTHER DTC OUTPUT


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch ON and turn the intelligent tester ON.

    3. Enter the following menus: Powertrain / Engine / DTC.

    4. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P0093/78 A
      P0093/78 and "P0200/97 and/or 1229/78" B

    B

    GO TO DTC CHART

    A

  2. CHECK FUEL LEAK (IN HIGH-PRESSURE FUEL PARTS AND AREAS)


    1. Visually check the supply pump, each injector and fuel line located between the supply pump and common rail for fuel leaks or fuel pressure leaks. Also, perform the same on the fuel line between the common rail and each injector Click here.

      Tech Tips

      There is possibility that fuel leaks inside the components (supply pump, etc.) have occurred.

      OK
      No leakage

    NG

    REPAIR OR REPLACE FUEL LEAKAGE POINT

    OK

  3. READ VALUE USING COMPENSATORY INJECTION VOLUME


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine and turn the intelligent tester ON.

    3. Enter the following menus: Powertrain / Engine / Data List / Injection Feedback Val #1, #2, #3 and #4.

    4. Read the values.

      OK
      Compensatory injection volume is between -4.9 mm3 and 4.9 mm3.

      Tech Tips


      • If the injector is malfunctioning, the compensatory injection volume remains between -5.0 mm3and 5.0 mm3.

      • The compensatory injection volume is usually between -3.0 mm3and 3.0 mm3.


    NG

    REPLACE INJECTOR ASSEMBLY

    OK

  4. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine and turn the intelligent tester ON.

    3. Enter the following menus: Powertrain / Engine / Active Test / Test the Fuel Leak.

    4. Check for fuel leaks in the high-ressure areas.


    NEXT

    CHECK IF DTC OUTPUT RECURS

When not using intelligent tester:

PROCEDURE


  1. CHECK DTC OUTPUT


    1. Turn the ignition switch ON.

    2. Read DTCs.

      Result
      Display (DTC output) Proceed to
      P0093/78 only A
      P0093/78 and P0200/97 B

    B

    GO TO DTC CHART

    A

  2. CHECK FUEL LEAK


    1. Visually check the supply pump, each injector and fuel line located between the supply pump and common rail for fuel leaks or fuel pressure leaks. Also, perform the same on the fuel line between the common rail and each injector Click here.

      OK
      No leakage.

      Tech Tips

      There is possibility that fuel leaks inside the components (supply pump, etc.) have occurred.


    NG

    REPAIR OR REPLACE FUEL LEAKAGE POINT

    OK

    REPLACE INJECTOR ASSEMBLY