GSIC - Global Service Information Center

### DTC P0627/78 Fuel Pump Control Circuit / Open

## for Preparation Click here

## DESCRIPTION

HINT:

  For more information on the supply pump (suction control valve) and the common rail system, refer to the system description (Click here).

DTC No. | DTC Detection Condition | Trouble Area

P0627/78

Open or short in suction control valve circuit for more than 0.5 seconds
(1 trip detection logic)

1. Open or short in suction control valve circuit
2. Suction control valve
3. ECM

HINT:

  When DTC P0627/78 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
  2,500 rpm (No engine load) | Approximately 35 to 55 MPa

## WIRING DIAGRAM

## INSPECTION PROCEDURE

HINT:

  Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

NOTICE:

1. If the ECM is replaced, the new ECM needs initialization (Click here).
2. If the supply pump is replaced, the ECM needs initialization (Click here).

1.INSPECT SUPPLY PUMP ASSEMBLY (SUCTION CONTROL VALVE)

1. Disconnect the S8 suction control valve connector.

1. Measure the resistance of the suction control valve.

   Standard resistance:
     1.9 to 2.3 Ω at 20°C (68°F)

| NG |

REPLACE SUPPLY PUMP ASSEMBLY

OK |

2.CHECK WIRE HARNESS (SUCTION CONTROL VALVE - ECM)

1. Disconnect the S8 valve connector.

1. Disconnect the E8 ECM connector.

1. Measure the resistance of the wire harness side connectors.

   Standard resistance:

     Tester Connection | Specified Condition
     S8-1 (PCV+) - E8-2 (PCV+) | Below 1 Ω
     S8-2 (PCV-) - E8-1 (PCV-) | Below 1 Ω
     S8-1 (PCV+) - E8-2 (PCV+) - Body ground | 10 kΩ or higher
     S8-2 (PCV-) - E8-1 (PCV-) - Body ground | 10 kΩ or higher

| NG |

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK |

3.CHECK ECM (PCV SIGNAL)

1. While cranking or idling the engine, check the waveform of the ECM connector using an oscilloscope.

   Standard voltage:

     Tester Connection | Specified Condition
     E8-2 (PCV+) - E8-1 (PCV-) | Correct waveform is shown

     Tool Setting | Condition
     10 V/DIV., 5 msec./DIV. | Idling or cranking with warm engine

   HINT:
     The waveform varies depending on the suction control valve operation.

| NG |

REPLACE ECM

OK |

CHECK FOR INTERMITTENT PROBLEMS