FC CONTROL SYSTEM, Diagnostic DTC:P1E49-450

DTC Code DTC Name
P1E49-450 Mass Air Flow Temperature Sensor Correlation

DESCRIPTION

The air system feeds the FC stack with a necessary amount of oxygen for power generation. The mass air flow meter, which is a part of the air system, has a built-in intake air temperature sensor that measures an ambient temperature for the FC stack. An intake air volume measured by the mass air flow meter is corrected in accordance with changes in an air temperature that is monitored by the intake air temperature sensor.

When an intake air temperature sensor value is compared to another sensor value that is supposed to be equal to the said sensor value, if it has deviated from other values by more than a threshold, it will be interpreted as occurrence of abnormal sensor deviation, and this DTC will be set.

For the circuit diagram, refer to DTC P0101-450.

Click here

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate
P1E49-450 Mass Air Flow Temperature Sensor Correlation

While the vehicle is traveling and the air compressor is operating, the intake air temperature sensor value of the mass air flow meter has significantly deviated from the ambient temperature value of the air conditioning amplifier.

(3 times)

 Mass air flow meter 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 - - - - ○ -
Related Data List
DTC No. System Data List
P1E49-450 FC Smoothed Value of Intake Air Temperature
Air Conditioner Ambient Temp Sensor

Tech Tips

This DTC will be output even if ambient temperature sensor values of the air conditioning amplifier are abnormal.

The following items can be helpful when performing repairs:


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.


  1. Drive the vehicle at a speed of approximately 40 to 60 km/h (25 to 37 mph) for at least 5 minutes (Vehicle does not have to run continuously at the speeds).

    CAUTION:

    Perform this road test only in an appropriate safe location, in accordance with all local laws.

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

    6. Turn the power switch off.

      Result
      Proceed to
      NEXT

    NEXT

  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 INTAKE AIR TEMPERATURE)


    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 / Smoothed Value of Intake Air Temperature


      Powertrain > FC > Data List
      Tester Display
      Smoothed Value of Intake Air Temperature
    5. A01MIATC01
      *1 Thermometer

      Remove the air cleaner cap sub-assembly, and measure the temperature around the mass air flow meter inside the air cleaner case sub-assembly.

    6. Compare the temperature around the mass air flow meter and the "Smoothed Value of Intake Air Temperature" in the Data List.

      Result
      Result Proceed to
      Except the following. A
      Difference between the "Smoothed Value of Intake Air Temperature" and the temperature around the mass air flow meter is more than 10°C (50°F). B

    7. Turn the power switch off.


    B

    REPLACE MASS AIR FLOW METER Click here

    A

  4. READ VALUE USING GTS (AMBIENT TEMP SENSOR)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Air Conditioner / Data List / Ambient Temp Sensor


      Body Electrical > Air Conditioner > Data List
      Tester Display
      Ambient Temp Sensor

    5. Measure the temperature around the ambient temperature sensor.

    6. Compare the temperature around the ambient temperature sensor and the Data List item "Ambient Temp Sensor".

      Note

      Ambient temperature sensor output is influenced by sunlight, so if the vehicle had been parked outdoor for a long time, a sensor value will increase.

      Result
      Result Proceed to
      Except the following. A
      Difference between Data List item "Ambient Temp Sensor" and temperature of area around ambient temperature sensor is 10°C (50°F) or more. B

    7. Turn the power switch off.


    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    GO TO AIR CONDITIONING SYSTEM Click here