FC CONTROL SYSTEM, Diagnostic DTC:P1D8C-450, P1D8D-450

DTC Code DTC Name
P1D8C-450 FC Stack Air Temperature Sensor (FC Stack Inlet) Circuit Low
P1D8D-450 FC Stack Air Temperature Sensor (FC Stack Inlet) Circuit High

DESCRIPTION

The FC gas temperature sensor is provided on the FC air compressor with motor assembly, and is used to monitor air temperature cooled down by the intercooler. The FC gas temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the intake air temperature is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the FC control ECU as voltage changes.

The FC gas temperature sensor is connected to the FC control ECU, and a power voltage of 5 V is supplied from the ATIC terminal of the FC control ECU to the sensor via resistor R. Since resistor R and the sensor are connected in series, resistance varies as an intake air temperature changes, and potential of the ATIC terminal also varies.

A01MGA3E05
DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate
P1D8C-450 FC Stack Air Temperature Sensor (FC Stack Inlet) Circuit Low

If the +B voltage is not low when the power switch is turned on (IG), FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage remains at less than 0.1 V for more than 3 seconds.

(1 trip detection logic)

  • FC gas temperature sensor

  • FC control ECU

  • Wire harness or connector

 Master Warning Light: Comes on
P1D8D-450 FC Stack Air Temperature Sensor (FC Stack Inlet) Circuit High

If all of the following conditions are met, and FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage remains at more than 4.95 V for more than 3 seconds.


  • FC Mode is in FC Startup Process or FC Working

  • Intake air temperature is more than 20°C (68°F)

  • Mass air flow meter is normal

  • +B voltage is not low

(1 trip detection logic)

  • FC gas temperature sensor

  • FC control ECU

  • Wire harness or connector

 Master Warning Light: Comes on
Detection timing: P1D8C-450
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 ○ ○ ○ ○ ○ -
Detection timing: P1D8D-450
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" and "FC Intermittent Operation" 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
P1D8C-450

  • FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage

  • Smoothed Value of FC Stack Air Temperature (FC Stack Inlet)
P1D8D-450

The following items can be helpful when performing repairs:


WIRING DIAGRAM

A01MJW9E09
*a ATIC
*b GATI
*c FC Gas Temperature Sensor
*d FC Control ECU

CAUTION / NOTICE / HINT

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

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


    P1D8C-450

  1. Turn the power switch on (IG) and wait for 3 seconds or more.


    P1D8D-450

  1. Wait for at least 3 seconds with the shift lever in P, the power switch on (READY), and the "FC Mode" in FC Working or FC Startup Process. Perform a check with the "Smoothed Value of Intake Air Temperature" is more than 20°C (68°F).

PROCEDURE


  1. READ VALUE USING GTS (FC STACK AIR TEMPERATURE SENSOR (FC STACK INLET) VOLTAGE)


    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 Stack Air Temperature Sensor (FC Stack Inlet) Voltage


      Powertrain > FC > Data List
      Tester Display
      FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage

    5. Read the value displayed on the GTS.

      Result
      FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage Proceed to
      Higher than 4.95 V A
      Less than 0.10 V B

      Tech Tips


      • If there is an open circuit, the GTS indicates higher than 4.95 V.

      • If there is a short circuit, the GTS indicates less than 0.10 V.


    B

    READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS) Click here

    A

  2. READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)


    1. A01MHHG

      Disconnect the FC gas temperature sensor connector.

    2. A01MHY6C01
      *1 FC Gas Temperature Sensor
      *2 FC Control ECU
      *a

      Front view of wire harness connector

      (to FC Gas Temperature Sensor)

      Connect terminals 1 (ATIC) and 2 (GATI) of the FC gas temperature sensor connector on the wire harness side.

    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 Stack Air Temperature Sensor (FC Stack Inlet) Voltage


      Powertrain > FC > Data List
      Tester Display
      FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage

    7. Read the value displayed on the GTS.

      Standard value
      Less than 0.10 V (Short circuit)

    8. Turn the power switch off.

    9. Reconnect the FC gas temperature sensor connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FC GAS TEMPERATURE SENSOR Click here

    NG

  3. CHECK HARNESS AND CONNECTOR (FC CONTROL ECU - FC GAS TEMPERATURE SENSOR)


    1. Disconnect the FC control ECU connector.

    2. Disconnect the FC gas temperature sensor connector.

    3. A01MGPOC01
      *a

      Front view of wire harness connector

      (to FC Gas Temperature Sensor)
      *b

      Front view of wire harness connector

      (to FC Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A48-56 (ATIC) - D3-1 (ATIC) Always Below 1 Ω
      A48-57 (GATI) - D3-2 (GATI) Always Below 1 Ω

    4. Reconnect the FC gas temperature sensor connector.

    5. Reconnect the FC control ECU connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FC CONTROL ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  4. READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)


    1. A01MHHG

      Disconnect the D3 FC gas temperature sensor connector.

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Turn the GTS on.

    5. A01MHH9C05
      *1 FC Gas Temperature Sensor
      *2 FC Control ECU

      Enter the following menus: Powertrain / FC / Data List / FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage


      Powertrain > FC > Data List
      Tester Display
      FC Stack Air Temperature Sensor (FC Stack Inlet) Voltage

    6. Read the value displayed on the GTS.

      Standard value
      Higher than 4.95 V (Open circuit)

    7. Turn the power switch off.

    8. Reconnect the D3 FC gas temperature sensor connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FC GAS TEMPERATURE SENSOR Click here

    NG

  5. CHECK HARNESS AND CONNECTOR (FC CONTROL ECU - FC GAS TEMPERATURE SENSOR)


    1. Disconnect the FC control ECU connector.

    2. Disconnect the FC gas temperature sensor connector.

    3. A01MGPOC02
      *a

      Front view of wire harness connector

      (to FC Gas Temperature Sensor)
      *b

      Front view of wire harness connector

      (to FC Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A48-56 (ATIC) or D3-1 (ATIC) - Body ground and other terminals Always 10 kΩ or higher

    4. Reconnect the FC control ECU connector.

    5. Reconnect the FC gas temperature sensor connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FC CONTROL ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR