FC CONTROL SYSTEM, Diagnostic DTC:P0112-450, P0113-450

DTC Code DTC Name
P0112-450 Intake Air Temperature Circuit Low Input
P0113-450 Intake Air Temperature Circuit High Input

DESCRIPTION

The intake air temperature sensor, mounted on the mass air flow meter, monitors the intake air temperature.

The intake air 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 intake air temperature sensor is connected to the FC control ECU, and a power voltage of 5 V is supplied from the AFMT 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 AFMT terminal also varies.

A01MHPOE11
DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate
P0112-450 Intake Air Temperature Circuit Low Input

If the +B voltage is not low when the power switch is on (IG), the output voltage of the intake air temperature sensor circuit remains at less than 0.1 V (short circuit) for more than 3 seconds.

(1 trip detection logic)

  • Mass air flow meter

  • FC control ECU

  • Wire harness or connector

 Master Warning Light: Comes on
P0113-450 Intake Air Temperature Circuit High Input

If the +B voltage is not low when the power switch is on (IG), the output voltage of the intake air temperature sensor circuit remains at more than 4.9V (open circuit) for more than 3 seconds.

(1 trip detection logic)

  • Mass air flow meter

  • FC control ECU

  • Wire harness or connector

 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 travelling)

 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. Data List
P0112-450 Smoothed Value of Intake Air Temperature
P0113-450

WIRING DIAGRAM

A01MHUZE01

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

PROCEDURE


  1. 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. Read the value displayed on the GTS.

      Result
      Smoothed Value of Intake Air Temperature Proceed to
      -40°C (Open circuit) A
      140°C (Short circuit) B

      Tech Tips


      • If there is an open circuit, the GTS indicates -40°C (-40°F).

      • If there is a short circuit, the GTS indicates 140°C (284°F).


    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. A01MJ84

      Disconnect the mass air flow meter connector.

    2. A01MI9JC02
      *1 Mass Air Flow Meter
      *2 FC Control ECU
      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter)

      Connect terminals 1 (THA) and 2 (E2) of the mass air flow meter 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 / Smoothed Value of Intake Air Temperature


      Powertrain > FC > Data List
      Tester Display
      Smoothed Value of Intake Air Temperature

    7. Read the value displayed on the GTS.

      Standard value
      140°C (284°F)

    8. Turn the power switch off.

    9. Reconnect the mass air flow meter connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MASS AIR FLOW METER Click here

    NG

  3. CHECK HARNESS AND CONNECTOR (FC CONTROL ECU - MASS AIR FLOW METER)


    1. Disconnect the FC control ECU connector.

    2. Disconnect the mass air flow meter connector.

    3. A01MIE6C05
      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter)
      *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
      A47-120 (AFMT) - A49-1 (THA) Always Below 1 Ω
      A47-97 (GAFT) - A49-2 (E2) Always Below 1 Ω

    4. Reconnect the mass air flow meter 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. A01MJ84

      Disconnect the mass air flow meter connector.

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Turn the GTS on.

    5. A01MHH9C01
      *1 Mass Air Flow Meter
      *2 FC Control ECU

      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

    6. Read the value displayed on the GTS.

      Standard value
      -40°C (-40°F)

    7. Turn the power switch off.

    8. Reconnect the mass air flow meter connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MASS AIR FLOW METER Click here

    NG

  5. CHECK HARNESS AND CONNECTOR (FC CONTROL ECU - MASS AIR FLOW METER)


    1. Disconnect the FC control ECU connector.

    2. Disconnect the mass air flow meter connector.

    3. A01MIE6C06
      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter)
      *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
      A47-120 (AFMT) or A49-1 (THA) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    4. Reconnect the mass air flow meter connector.

    5. Reconnect the FC control ECU connector.


    OK

    REPLACE FC CONTROL ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR