ECD SYSTEM, Diagnostic DTC:78(1)

DTC Code DTC Name
78(1) Fuel Pump Circuit Malfunction (Fuel Leakage)

DESCRIPTION

Refer to DTC 49 on page Click here

Refer to DTC 97 on page Click here

78 (1) Pressure change of common rail is abnormal against injection quantity and supply quantity of supply pump

  • Open or short in EDU circuit

  • EDU

  • Open or short in injector circuit

  • Injector

  • Open or short in common rail pressure sensor circuit

  • Common rail pressure sensor (built into common rail)

  • Fuel line between supply pump and common rail

  • Fuel line between common rail and injector

  • Pressure limiter (built into common rail)

  • ECM

WIRING DIAGRAM

Refer to DTC No. 49 on page Click here

Refer to DTC No. 97 on page Click here

INSPECTION PROCEDURE

Tech Tips


  • Read freeze frame data using intelligent tester. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

  • When not using the intelligent tester go to step 8.

PROCEDURE


  1. ARE THERE ANY OTHER CODES BEING OUTPUT? (BESIDE DTC 39, DTC 49, DTC 78(2), DTC 78(3), OR DTC 97)


    YES

    GO TO RELEVANT DTC CHART Click here

    NO

  2. CHECK FUEL LEAKAGE

    Click here


    NG

    CHECK AND REPLACE A PLACE FUEL LEAKS

    OK

  3. CHECK ECM (CHECK VOLTAGE)


    1. A01KGF1E07

      Turn the ignition switch ON.

    2. Check the voltage between terminals of the ECM connector as shown in the table and illustration.

      Voltage (at 20°C (68°F))

      Terminal

      (Positive terminal ←→ Negative terminal)

      		 Voltage
      PCR (E8-23) ←→ E2 (E8-20) Approx. 1 V

    OK

    READ VALUE OF INTELLIGENT TESTER (COMPENSATION OF INJECTION QUANTITY BETWEEN CYLINDERS) Click here

    NG

  4. CHECK WIRE HARNESS (ECM - FUEL PRESSURE SENSOR FOR COMMON RAIL)


    1. A01KF5GE02

      Disconnect the fuel pressure sensor for common rail connector.

    2. Disconnect the ECM (E8) connector.

    3. Check the continuity between terminals of the fuel pressure sensor for common rail and ECM connectors as shown in the illustration and table.

      Continuity (Check for open)

      Terminal

      (Fuel pressure sensor for common rail ←→ ECM)

      		 Standard
      VOUT (2) ←→ PCR (E8-23) Continuity
      VCC (3) ←→ VC (E8-21)
      GND (1) ←→ E2 (E8-20)
      Continuity (Check for short)

      Terminal

      (ECM ←→ ECM(Ground))

      		 Standard
      PCR (E8-23) ←→ E1 (E7-22) No continuity
      VC (E8-21) ←→ E1 (E7-22)

    OK

    REPLACE COMMON RAIL ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

  5. READ VALUE OF INTELLIGENT TESTER (COMPENSATION OF INJECTION QUANTITY BETWEEN CYLINDERS)


    1. Connect the hand held tester to the DLC3.

    2. Turn the ignition switch ON and push the intelligent tester main switch ON.

    3. Read the compensation of the injection quantity between the cylinders on the intelligent tester.

      STD
      -3 - 3 mm3/st
      Maximum
      -4 - 4 mm3/st

    NG

    REPLACE INJECTOR ASSEMBLY Click here

    OK

  6. CHECK IF ANY FUEL IS MIXED WITH ENGINE OIL


    NG

    REPLACE INJECTOR ASSEMBLY Click here

    OK

  7. CHECK THAT IF ANY WHITE SMOKE IS COMING OUT


    OK

    REPLACE INJECTOR ASSEMBLY Click here

    OK

    REPLACE COMMON RAIL ASSEMBLY Click here

    NG

    REPLACE INJECTOR ASSEMBLY Click here

  8. ARE THERE ANY OTHER CODES BEING OUTPUT? (BESIDE DTC 39, DTC 49, DTC 78(2), DTC 78(3), OR DTC 97)


    YES

    GO TO RELEVANT DTC CHART Click here

    NO

  9. CHECK FUEL LEAKAGE

    Click here


    NG

    CHECK AND REPLACE A PLACE FUEL LEAKS

    OK

  10. CHECK ECM (CHECK VOLTAGE)


    1. A01KGF1E07

      Turn the ignition switch ON.

    2. Check the voltage between terminals of ECM connector as shown in the table and illustration.

      Voltage (at 20°C (68°F))

      Terminal

      (Positive terminal ←→ Negative terminal)

      		 Voltage
      PCR (E8-23) ←→ E2 (E8-20) Approx. 1 V

    NG

    CHECK IF ANY FUEL IS MIXED WITH ENGINE OIL Click here

    OK

  11. CHECK WIRE HARNESS (ECM - FUEL PRESSURE SENSOR)


    1. A01KF5GE02

      Disconnect the turbo pressure sensor for common rail connector.

    2. Disconnect the ECM E8 connector.

    3. Check the continuity between terminals of the fuel pressure sensor for common rail and ECM connectors as shown in the illustration and table.

      Standard (Check for open)

      Terminal

      (Fuel pressure sensor for common rail ←→ ECM)

      		 Standard
      VOUT (2) ←→ PCR (E8-23) Continuity
      VCC (3) ←→ VC (E8-21)
      GND (1) ←→ E2 (E8-20)
      Standard (Check for short)

      Terminal

      (ECM ←→ ECM(Ground))

      		 Standard
      PCR (E8-23) ←→ E1 (E7-22) No continuity
      VC (E8-21) ←→ E1 (E7-22)

    OK

    REPLACE COMMON RAIL ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

  12. CHECK IF ANY FUEL IS MIXED WITH ENGINE OIL


    NG

    REPLACE INJECTOR ASSEMBLY Click here

    OK

  13. CHECK THAT IF ANY WHITE SMOKE IS COMING OUT


    NG

    REPLACE INJECTOR ASSEMBLY Click here

    OK

    GO TO EACH DTC CHART (GO TO STEP 1 IN DTC 78(2), DTC 78 (3))