FC CONTROL SYSTEM, Diagnostic DTC:P1DC0-450

DTC Code DTC Name
P1DC0-450 Low-range Hydrogen Pressure Too Low

DESCRIPTION

The hydrogen system of the FC system feeds the FC stack with compressed hydrogen, so that the FC stack can generate power. The low-range pressure circuit is located after the hydrogen injectors, and pressure applied to the circuit is regulated by the hydrogen injectors to an appropriate level for FC stack power generation.

If the regulated low-range hydrogen pressure (applied to the area after the hydrogen injectors) decreases below a threshold, the FC control ECU interprets it as a lower pressure limit error, and sets this DTC.

B000ZSLC01
*1 Hydrogen Inlet Receptacle Assembly *2 Hydrogen Tank Pressure Sensor (for Inlet Side)
*3 No. 1 Hydrogen Tank Assembly *4 No. 2 Hydrogen Tank Assembly
*5 Hydrogen Tank Temperature Sensor 1 *6 Hydrogen Tank Temperature Sensor 2
*7 Tank Shut Valve 1 *8 Tank Shut Valve 2
*9 Hydrogen Tank Pressure Sensor (for Outlet Side) *10 Hydrogen Supply Regulator Assembly
*11 Medium-range Hydrogen Pressure Sensor *12 Hydrogen Injector
*13 Low-range Hydrogen Pressure Sensor *14 FC Stack
*15 FC Stack Assembly *16 Hydrogen Pump
*17 Exhaust Drainage Valve *18 Air Shunt Valve
*19 Air Pressure Regulating Valve *20 Manual Valve
*21 Pressure Relief Valve *22 Pressure Relief Device
*a Hydrogen System *b Air System
*c From the FC Air Compressor with Motor Assembly *d To the Exhaust Drainage Pipe
*e Low-range Pressure Circuit - -
DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate
P1DC0-450 Low-range Hydrogen Pressure Too Low

Low-range hydrogen pressure has decreased below the low pressure limit. This malfunction detection is performed when the FC Mode is in FC Working or FC Shutdown Process.

(1 trip detection logic)

  • High-range hydrogen pressure pipe

  • Medium-range hydrogen pressure pipe

  • Hydrogen supply regulator assembly

  • FC stack assembly (hydrogen injector, exhaust drainage valve, low-range hydrogen pressure sensor, Low-range hydrogen pressure pipe, FC stack)

 Master Warning Light: Comes on
Detection timing
Vehicle Condition

FC shutdown

(power switch on (IG))

 FC startup process FC intermittent operation

FC is generating power

(vehicle is in stationary)

FC is generating power

(vehicle is traveling)

 FC shutdown process

Data List

"FC Mode"

 FC Shutdown FC Startup Process FC Working FC Shutdown Process

Data List

"FC Intermittent Operation"

 OFF ON OFF OFF
DTC Detection - - ○ ○ ○ ○

Tech Tips

By accessing the "FC Mode" in the freeze frame data, the FC system condition at the time the malfunction occurred can be checked.

Related Data List
DTC No. Data List
P1DC0-450

  • Smoothed Value of Low-range Hydrogen Pressure

  • Target Low-range Hydrogen Pressure

The following items can be helpful when performing repairs:



Related Active Test
DTC No. Active Test
P1DC0-450 Hydrogen Injector

CAUTION / NOTICE / HINT

CAUTION:


  • B006JCR

    Work procedures must be performed in an area with good ventilation (airflow) where hydrogen gas will not accumulate, and flames or other things that could act as ignition sources must not be present.

  • Accumulated hydrogen gas could ignite, resulting in a serious accident.

    Click here

Note

When the vehicle is parked with the power switch off, if the FC control ECU judges that the FC stack temperature will go below 0°C (32°F), it activates the FC air compressor, hydrogen pump and FC cooling water pump for a maximum of 180 seconds and drains water from the FC stack assembly. When performing inspection or repairs with the power switch off (not on (IG) or on (READY)), disconnect the cable from the negative (-) auxiliary battery terminal before performing work (If the auxiliary battery voltage is needed to conduct inspection, warm up the FC system beforehand).

Tech Tips


  • Forcing the SOC of the EV battery to decrease by applying electrical loads such as turning on the air conditioning (HOT MAX, maximum airflow), or depressing the accelerator pedal with the shift lever in P, the "FC Intermittent Operation" of the Data List is easily to enter OFF (power generation mode).

  • After completion of repair, check that no hydrogen leaks from the hydrogen system components with a hydrogen gas detector.

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Turn the power switch on (READY) with the shift lever in P, and check the Data List that "FC Mode" is FC Working.

    Then, wait 2 minutes or more. Check that the "Smoothed Value of Low-range Hydrogen Pressure" in the Data List is between "an atmospheric pressure plus 10 kPa" and "280 kPa(abs)".

PROCEDURE


  1. CHECK DTC OUTPUT

    Note

    The freeze frame data is cleared when DTCs are cleared. Be sure to make a note of necessary data in advance.


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / FC / Trouble Codes.

    5. Check for DTCs.


      Powertrain > FC > Trouble Codes
      Result
      Result Proceed to
      P1DC0-450 only is output, or DTCs except the ones in the table below are also output. A
      Any of the following DTCs are also output. B
      Malfunction Content Relevant DTC
      Sensor and Actuator Circuit Malfunction P1D9C-450 Hydrogen Injector No. 1 Circuit Low
      P1D9D-450 Hydrogen Injector No. 1 Circuit High
      P1DA2-450 Hydrogen Injector No. 2 Circuit Low
      P1DA3-450 Hydrogen Injector No. 2 Circuit High
      P1DA7-450 Hydrogen Injector No. 3 Circuit Low
      P1DA8-450 Hydrogen Injector No. 3 Circuit High
      P1DAC-450 Exhaust Drainage Valve Circuit Low
      P1DAD-450 Exhaust Drainage Valve Circuit High
      P1DBC-450 Low-range Hydrogen Pressure Sensor Circuit Low
      P1DBD-450 Low-range Hydrogen Pressure Sensor Circuit High
      System Malfunction P1E42-450 Hydrogen Pressure Leak (Excessive Hydrogen Flow)
      P1E43-450 Hydrogen Pressure Leak (High/Medium Pressure Area)
      P1E44-450 Hydrogen Pressure Leak (Low Pressure Area)

      Tech Tips

      P1DC0-450 may be set due to problems that cause the DTCs shown above to be output. If such happens, troubleshoot the suspected area(s) corresponding to the output DTC(s) in order of the listed DTCs shown in the table above.

    6. Turn the power switch off.


    B

    GO TO DTC CHART Click here

    A

  2. CLEAR DTC


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / FC / Trouble Codes.

    5. Clear the DTCs.


      Powertrain > FC > Clear DTCs

    6. Turn the power switch off and wait for 3 minutes or more.

      Result
      Proceed to
      NEXT

    NEXT

  3. READ VALUE USING GTS (SMOOTHED VALUE OF HIGH-RANGE HYDROGEN PRESSURE)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (READY).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / FC / Data List / Smoothed Value of High-range Hydrogen Pressure


      Powertrain > FC > Data List
      Tester Display
      Smoothed Value of High-range Hydrogen Pressure

    5. Read the value displayed on the GTS.

      Result
      Result Proceed to
      "Smoothed Value of High-range Hydrogen Pressure" in the Data List is less than 5000 kPa(abs) A
      Other than above B

    6. Turn the power switch off.


    B

    GO TO STEP 5 Click here

    A

  4. CHARGE HYDROGEN GAS


    1. Fill the tank until the "Smoothed Value of High-range Hydrogen Pressure" in the Data List exceeds 5000 kPa(abs).

      Result
      Proceed to
      NEXT

    NEXT

  5. READ VALUE USING GTS (SMOOTHED VALUE OF MEDIUM-RANGE HYDROGEN PRESSURE)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (READY).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / FC / Data List / Smoothed Value of Medium-range Hydrogen Pressure


      Powertrain > FC > Data List
      Tester Display
      Smoothed Value of Medium-range Hydrogen Pressure

    5. Read the value displayed on the GTS.

      Result
      Result Proceed to
      Except the following A
      "Smoothed Value of Medium-range Hydrogen Pressure" in the Data List is 600 kPa(abs) or less B

    6. Turn the power switch off.


    B

    REPLACE HYDROGEN SUPPLY REGULATOR ASSEMBLY Click here

    A

  6. PERFORM ACTIVE TEST USING GTS (HYDROGEN INJECTOR)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / FC / Active Test / Hydrogen Injector

    5. Select "FC Mode", "FC Intermittent Operation", "Hydrogen Injector 1 Injection Request", "Hydrogen Injector 2 Injection Request", "Hydrogen Injector 3 Injection Request" and "Smoothed Value of Low-range Hydrogen Pressure" in the Data List.


      Powertrain > FC > Active Test
      Active Test Display
      Hydrogen Injector
      Data List Display
      FC Mode
      FC Intermittent Operation
      Hydrogen Injector 1 Injection Request
      Hydrogen Injector 2 Injection Request
      Hydrogen Injector 3 Injection Request
      Smoothed Value of Low-range Hydrogen Pressure

    6. Turn the power switch on (READY) with the shift lever in P, and check the Data List that "FC Mode" is FC Working and "FC Intermittent Operation" is OFF.

    7. While performing the "Hydrogen Injector" Active Test, check "Hydrogen Injector 1 Injection Request", "Hydrogen Injector 2 Injection Request", "Hydrogen Injector 3 Injection Request" and "Smoothed Value of Low-range Hydrogen Pressure" in the Data List.

      Note

      If the Active Test is disabled, check the "Hydrogen Injector Injection Requests (1, 2 and 3)" and the "Smoothed Value of Low-range Hydrogen Pressure" in the Data List at the time the "FC Mode" is in the FC Startup Process.

      Figure 1. Reference example

      B000ZO6E01
      Result
      Result Proceed to
      For each hydrogen injector, their "Smoothed Value of Low-range Hydrogen Pressures" in the Data List increase by more than 5 kPa per injection. A
      Other than above* B

      • *: The hydrogen injector is malfunctioning


    B

    REPLACE FC STACK ASSEMBLY Click here

    A

  7. CHECK EXHAUST HYDROGEN GAS

    CAUTION:


    • Work procedures must be performed in an area with good ventilation (airflow) where hydrogen gas will not accumulate, and flames or other things that could act as ignition sources must not be present.

    • Accumulated hydrogen gas could ignite, resulting in a serious accident.


    1. Ensure the safety of the areas in front and at the back of the vehicle.

    2. Put wheel chocks and securely apply the parking brake.

    3. Connect the GTS to the DLC3.

    4. Turn the power switch on (IG).

    5. Turn the GTS on.

    6. Enter the following menus: Powertrain / FC / Data List / FC Mode, FC Intermittent Operation, Exhaust Drainage Valve Driving Request


      Powertrain > FC > Data List
      Tester Display
      FC Mode
      FC Intermittent Operation
      Exhaust Drainage Valve Driving Request
    7. B000ZTSC01
      *1 Tailpipe
      *2 Hydrogen gas detector probe

      Using a hydrogen gas detector, measure the hydrogen concentration in the gas emitted from the tail pipe.

      Note


      • Perform this measurement in an environment where there is no wind.

      • Position the hydrogen gas detector probe in an area 100 mm (3.94 in.) away from the tailpipe opening. (Avoid locations underneath the tailpipe opening)

      • Position the hydrogen gas detector probe so that it is free from dropping water that comes from the tailpipe opening.

    8. Measure the hydrogen concentration for 1 minute with the shift lever in P, the power switch on (READY), the Data List "FC Mode" showing FC Working and "FC Intermittent Operation" showing OFF. Watch for changes in the concentration when the "Exhaust Drainage Valve Driving Request" is ON and OFF in the Data List.

      Note

      Start measurement immediately after the power switch is turned on (READY).

    9. Turn the power switch off.

      Result
      Result Proceed to
      Hydrogen concentration increases when the "Exhaust Drainage Valve Driving Request" is ON but does not increase when it is OFF. A
      Other than above* B

      • *: The exhaust drainage valve is malfunctioning

      • Exhaust drainage valve is stuck closed:


        • Regardless of the "Exhaust Drainage Valve Driving Request" being ON or OFF, the concentration shown on the hydrogen gas detector has remained low.

      • Exhaust drainage valve is stuck open:


        • Regardless of the "Exhaust Drainage Valve Driving Request" being ON or OFF, the concentration shown on the hydrogen gas detector has remained high when the power switch is on (READY).


    B

    REPLACE FC STACK ASSEMBLY Click here

    A

  8. CHECK DTC OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / FC / Data List / FC Mode, Smoothed Value of Low-range Hydrogen Pressure


      Powertrain > FC > Data List
      Tester Display
      FC Mode
      Smoothed Value of Low-range Hydrogen Pressure

    5. Turn the power switch on (READY) with the shift lever in P, and check the Data List that "FC Mode" is FC Working. Then, wait 2 minutes or more.

    6. Read the "Smoothed Value of Low-range Hydrogen Pressure" of the Data List.

    7. Enter the following menus: Powertrain / FC / Trouble Codes.

    8. Check for DTCs.


      Powertrain > FC > Trouble Codes
      Result
      Result Proceed to
      "Smoothed Value of Low-range Hydrogen Pressure" of the Data List is more than an atmospheric pressure plus 10 kPa, and DTC P1DCO-450 is not output. A
      Other than above B

    9. Turn the power switch off.


    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE FC STACK ASSEMBLY Click here