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 30 to 40 MPa
3,000 rpm (No engine load)
Approximately 50 to 70 MPa


WIRING DIAGRAM


A099786E04


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

1.INSPECT SUPPLY PUMP ASSEMBLY (SUCTION CONTROL VALVE)
A098438E02

  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)
A099839E03

  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)
A099840E02

  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