SFI SYSTEM, Diagnostic DTC:P1235

DTC Code DTC Name
P1235 High Pressure Fuel Pump Circuit

DESCRIPTION

The fuel pump for high pressure is attached to the insulator, which is attached to the cylinder head cover. The pump activates according to the position of the cam on the exhaust side camshaft (right bank).

The fuel pump for high pressure increases the pressure of the fuel supplied from the fuel pump in the fuel tank to 4000 to 13000 kPa (40.8 to 132.6 kgf/cm2, 580 to 1886 psi) according to the operating condition, and it feeds the fuel to the fuel delivery pipe.

DTC No. DTC Detection Condition Trouble Area
P1235

Open or short in high pressure side fuel pump circuit for 1 second or more

(1 trip detection logic)

  • Open or short in fuel pump for high pressure

  • Fuel pump for high pressure

  • Injector driver (EDU)

  • ECM

MONITOR DESCRIPTION

The injector driver has the integrated circuit (IC) which monitors the electrical circuit between the spill control valve and injector driver. If an open circuit is detected, the IC sends the malfunction signal (FPD) to the ECM. Then, the ECM illuminates the MIL and sets a DTC immediately.

MONITOR STRATEGY

Required Sensors/Components Fuel pump for high pressure
Frequency of Operation Continuous

CONFIRMATION DRIVING PATTERN


  1. Connect the GTS to the DLC3.

  2. Turn the engine switch on (IG) and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Click here.

  4. Turn the engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the GTS on.

  6. Start the engine.

  7. Idle the engine for 10 seconds [A].

  8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [B].

  9. Read Pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  10. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  11. Input the DTC: P1235.

  12. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform steps [A] and [B] again.

WIRING DIAGRAM

A01FH00E03

INSPECTION PROCEDURE

Tech Tips


  • If the current from the INJ relay is cut because DTC P062D is stored, DTC P1235 will be stored even if the fuel pump for high pressure is normal.

  • Read freeze frame data using the GTS. 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 moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. INSPECT FUEL PUMP FOR HIGH PRESSURE


    1. Inspect the fuel pump for high pressure Click here.


    NG

    REPLACE FUEL PUMP FOR HIGH PRESSURE Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (INJECTOR DRIVER - FUEL PUMP FOR HIGH PRESSURE)


    1. Disconnect the injector driver (EDU) connector.

    2. Disconnect the fuel pump for high pressure connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F37-3 (FP+) - F61-1 (FP+) Always Below 1 Ω
      F37-4 (FP-) - F61-2 (FP-) Always Below 1 Ω
      F37-3 (FP+) or F61-1 (FP+) - Body ground Always 10 kΩ or higher
      F37-4 (FP-) or F61-2 (FP-) - Body ground Always 10 kΩ or higher

    4. Reconnect the injector driver (EDU) connector.

    5. Reconnect the fuel pump for high pressure connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (ECM - INJECTOR DRIVER)


    1. Disconnect the ECM connector.

    2. Disconnect the injector driver (EDU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F3-10 (FPF1) - F36-7 (FPF1) Always Below 1 Ω
      F3-11 (FPD) - F36-8 (FPD) Always Below 1 Ω
      F3-10 (FPF1) or F36-7 (FPF1) - Body ground Always 10 kΩ or higher
      F3-11 (FPD) or F36-8 (FPD) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the injector driver (EDU) connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT ECM (FPD VOLTAGE)


    1. Turn the engine switch on (IG).

    2. Inspect the ECM using an oscilloscope.


      1. While cranking the engine, check the waveform the terminals of the ECM connector.

        ECM Terminal Name F3-11 (FPD) - F4-1 (E1)
        Tester Range 2 V/DIV., 5 ms./DIV.
        Condition Cranking
        A01FGH4E07
        Standard
        Signal waveform appears as shown in the illustration.
        Text in Illustration
        *a

        Component with harness connected

        (ECM)

        		 *b FPD Terminal Waveform Normal Waveform

        Tech Tips

        The FPD terminal waveform is output only right after the engine starts. If this DTC is stored when the engine is started from engine switch off, the system enters fail-safe mode and the waveform is not output.


    NG

    INSPECT ECM (FPD VOLTAGE) Click here

    OK

  5. INSPECT ECM (FPD AND FPF1 VOLTAGE)


    1. Turn the engine switch on (IG).

    2. Inspect the ECM using an oscilloscope.


      1. While cranking the engine, check the waveform the terminals of the ECM connector.

        ECM Terminal Name

        CH1: F3-11 (FPD) - F4-1 (E1)

        CH2: F3-10 (FPF1) - F4-1 (E1)
        Tester Range 2 V/DIV., 5 ms./DIV.
        Condition Cranking
        A01FI1WE04

        Tech Tips

        FPD terminal waveform is output only right after the engine starts.

      Result
      FPD Terminal Waveform FPF1 Terminal Waveform Proceed to
      OK OK A
      OK NG waveform 1* Does not change from NG waveform 1 (FPF1 terminal waveform remains at GND even after disconnecting the injector driver (EDU) connector and cranking the engine) A
      Changes to NG waveform 2 (FPF1 terminal waveform rises from GND after disconnecting the injector driver (EDU) connector and cranking the engine) B
      OK NG waveform 2 B
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      		 *b FPD Terminal and FPF1 Terminal Waveform Normal Waveform
      *c FPF1 Terminal Waveform NG Waveform 1 *d FPF1 Terminal Waveform NG Waveform 2

      Tech Tips

      *: If the FPF1 terminal waveform is similar to the FPF1 terminal waveform NG waveform 1, stop the engine and disconnect F36 injector driver (EDU) connector. Then, while cranking the engine, check to see if there is a difference between the FPF1 terminal waveform and the previous one.


    B

    REPLACE INJECTOR DRIVER Click here

    A

    REPLACE ECM Click here

  6. INSPECT ECM (FPD VOLTAGE)


    1. Turn the engine switch on (IG).

    2. Disconnect the F36 injector driver (EDU) connector.


      1. While cranking the engine, check the waveform the terminals of the ECM connector.

        ECM Terminal Name F3-11 (FPD) - F4-1 (E1)
        Tester Range 2 V/DIV., 5 ms./DIV.
        Condition Cranking
        A01FGH4E07
        Standard
        Signal waveform appears as shown in the illustration.
        Text in Illustration
        *a

        Component with harness connected

        (ECM)

        		 *b FPD Terminal Waveform Normal Waveform

        Tech Tips

        FPD terminal waveform is output only right after the engine starts.


    NG

    REPLACE ECM Click here

    OK

    REPLACE INJECTOR DRIVER Click here