DTC    P1271    Fuel Regulator Circuit Malfunction (EDU Drive)

for Preparation Click here


DESCRIPTION

Based on signals from the ECM, the pressure control valve opens when sudden deceleration occurs or when the ignition switch is turned off, to prevent the fuel pressure from becoming too high.

P1271 
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Ignition switch ON for 1 second
Open or short in pressure control valve circuit.
(1 trip detection logic)
  1. Open or short in pressure control valve circuit
  2. Common rail assembly (pressure control valve)
  3. ECM

HINT:
When the fuel temperature is less than 10°C (50°F), both the pressure control valve and fuel metering unit act in union for control the fuel pressure to the target fuel pressure.


WIRING DIAGRAM


A198995E03


INSPECTION PROCEDURE

NOTICE:
  1. When replacing the ECM, the ECM needs Registration and Initialization (Click here).
  2. Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:
  1. When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the intelligent tester. Then after installing the new ECM, perform all of the initializations/registrations for the "Learning Values Write" function by following the instructions shown on the tester display.
  2. Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are 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.

1.INSPECT COMMON RAIL ASSEMBLY (PRESSURE CONTROL VALVE)


    A122654E02

  1. Disconnect the pressure control valve connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 - 2
    		20°C (68°F)
    		3.42 to 3.78 Ω

    Text in Illustration 
    *1
    		Component without harness connected
    (Pressure Control Valve)

  1. Reconnect the pressure control valve connector.



NG
Go to step 9
OK


2.CHECK HARNESS AND CONNECTOR (PRESSURE CONTROL VALVE - ECM)


    A200291E03

  1. Disconnect the pressure control valve connector.

  1. Disconnect the ECM connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    B43-2 - B9-4 (PRV)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    B43-2 or B9-4 (PRV) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Pressure Control Valve)
    *2
    		Front view of wire harness connector
    (to ECM)

  1. Reconnect the pressure control valve connector.

  1. Reconnect the ECM connector.



NG
Go to step 8
OK


3.CHECK HARNESS AND CONNECTOR (POWER SOURCE)


    A200335E04

  1. Disconnect the pressure control valve connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    B43-1 - Body ground
    		Ignition switch ON
    		11 to 14 V

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Pressure Control Valve)

  1. Reconnect the pressure control valve connector.



NG
Go to step 6
OK


4.CHECK WHETHER DTC OUTPUT RECURS

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (Click here).

  1. Turn the ignition switch off and wait for 30 seconds or more.

  1. Turn the ignition switch to ON and wait for 1 second or more.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Read the DTCs.
    Result 
    Result
    		Proceed to
    No DTC output
    		A
    DTC P1271
    		B



B
Go to step 5
A

CHECK FOR INTERMITTENT PROBLEMS (Click here)  

5.REPLACE ECM

  1. Replace the ECM (Click here).



NEXT
Go to step 11

6.CHECK HARNESS AND CONNECTOR (PRESSURE CONTROL VALVE - INTEGRATION RELAY)


    A200297E02

  1. Disconnect the pressure control valve connector.

  1. Disconnect the integration relay connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    B43-1 - 1F-10
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    B43-1 or 1F-10 - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Pressure Control Valve)
    *2
    		Front view of wire harness connector
    (to Integration Relay)

  1. Reconnect the pressure control valve connector.

  1. Reconnect the integration relay connector.



NG
Go to step 8
OK


7.CHECK ECM POWER SOURCE CIRCUIT

  1. Check ECM power source circuit (Click here).



NEXT
Go to step 11

8.REPAIR OR REPLACE HARNESS OR CONNECTOR


NEXT
Go to step 11

9.REPLACE COMMON RAIL ASSEMBLY

  1. Replace the common rail assembly (Click here).


NEXT


10.BLEED AIR FROM FUEL SYSTEM

  1. Bleed air from fuel system (Click here).


NEXT


11.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (Click here).

  1. Turn the ignition switch off and wait for 30 seconds or more.

  1. Turn the ignition switch to ON and wait for 1 second or more.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Confirm that the DTC is not output again.


NEXT

END