AIR CONDITIONING SYSTEM, Diagnostic DTC:B14B8

DTC Code DTC Name
B14B8 Refrigerant Shortage

DESCRIPTION

This DTC is stored if the amount of refrigerant in the air conditioning system is insufficient.

The air conditioning amplifier assembly receives the ambient temperature signal, refrigerant pressure signal, etc. from various sensors.

Based on these signals, the air conditioning amplifier assembly detects the amount of refrigerant.

The A/C switch indicator is turned off and the air conditioning system is stopped if the amount of refrigerant is insufficient.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B14B8 Refrigerant Shortage

  • Diagnosis condition: At the time of quantity of refrigerant opinion on infringement condition establishment by the ordinary control

  • Malfunction status: When following condition is detected in refrigerant shortage check in normal operation; Amount of refrigerant is insufficient

  • Detection time: During air conditioning system operation for 10 minutes or more

  • Refrigerant pipe line (leaks, stuck)

  • Cooler expansion valve

  • Air conditioning amplifier assembly

  • Lack of refrigerant

 Memorized

WIRING DIAGRAM

B000PN8E16
*a Air Conditioner Pressure Sensor
*b Air Conditioning Amplifier Assembly

PROCEDURE


  1. CHECK REFRIGERANT PRESSURE


    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.

    5. Read the Data List according to the display on the GTS.


      Body Electrical > Air Conditioner > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Regulator Pressure Sensor Air conditioner pressure sensor

      Min.: -456.6 kPaG

      Max.: 3294.3 kPaG

      		 Actual refrigerant pressure displayed

      • Refrigerant line (gad leak etc.)

      • Air conditioner pressure sensor system malfunction

      Body Electrical > Air Conditioner > Data List
      Tester Display
      Regulator Pressure Sensor

    6. Install a manifold gauge set.

      for HFC-134a (R134a): Click here

      for HFO-1234yf (R1234yf): Click here

    7. Read the manifold gauge pressure when the following conditions are met.


      1. Prepare the vehicle according to the table below.

        Measurement Condition:
        Item Condition
        Vehicle doors Fully open
        Temperature setting MAX COLD
        Blower speed HI
        A/C switch On
        Recirculation/fresh switch RECIRCULATION
        Interior temperature 25 to 35°C (77 to 95°F)
      Standard Pressure
      Low pressure side
      150 to 250 kPa (1.5 to 2.5 kgf/cm2, 22 to 36 psi)
      High pressure side
      1370 to 1570 kPa (14 to 16 kgf/cm2, 199 to 228 psi)

    8. Compare the values displayed in the Data List and on the manifold gauge.

      OK
      The values displayed in the Data List and on the manifold gauge match.
      Result
      Proceed to
      OK
      NG

    NG

    GO TO ON-VEHICLE INSPECTION (CHECK REFRIGERANT PRESSURE USING GAUGE) Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B000RJDC03
      *a

      Front view of wire harness connector

      (to Air Conditioner Pressure Sensor)

      Disconnect the air conditioner pressure sensor connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A39-3 (+) - Body ground Power switch on (IG) 4.75 to 5.25 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - AIR CONDITIONER PRESSURE SENSOR) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - BODY GROUND)


    1. B000RJDC04
      *a

      Front view of wire harness connector

      (to Air Conditioner Pressure Sensor)

      Disconnect the air conditioner pressure sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A39-1 (-) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - AIR CONDITIONER PRESSURE SENSOR) Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - AIR CONDITIONER PRESSURE SENSOR)


    1. Disconnect the P57 air conditioning amplifier assembly connector.

    2. Disconnect the A39 air conditioner pressure sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P57-24 (PRE) - A39-2 (PR) Always Below 1 Ω
      P57-24 (PRE) or A39-2 (PR) - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY (SENSOR SIGNAL CIRCUIT)


    1. Measure the voltage when the following conditions are met.

      Measurement Condition:
      Item Condition
      Vehicle doors Fully open
      Temperature setting MAX COLD
      Blower speed HI
      A/C switch On
      Recirculation/fresh switch RECIRCULATION
      Interior temperature 25 to 35°C (77 to 95°F)

      Note


      • If refrigerant pressure on the high pressure side becomes extremely high during the inspection (if the voltage exceeds 4.61 V), the fail-safe function stops compressor operation. Therefore, measure the voltage before the fail-safe operation.

      • It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the malfunction may recur after a while.

      Tech Tips

      When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to operation of the thermistor assembly and the No. 1 cooler thermistor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.


      1. B000RL5C02
        *a

        Component with harness connected

        (Air Conditioning Amplifier Assembly)

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        P57-24 (PRE) - Body ground

        • Power switch on (IG)

        • A/C switch: On

        		 0.62 to 4.73 V (While sensor voltage is 5 V)

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Turn the GTS on.

    5. Enter the following menus: Body Electrical / Air Conditioner / Data List.

    6. Read the Data List according to the display on the GTS.


      Body Electrical > Air Conditioner > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Regulator Pressure Sensor Air conditioner pressure sensor

      Min.: -456.6 kPaG

      Max.: 3294.3 kPaG

      		 Actual refrigerant pressure displayed

      • Refrigerant line (gad leak etc.)

      • Air conditioner pressure sensor system malfunction

      Body Electrical > Air Conditioner > Data List
      Tester Display
      Regulator Pressure Sensor
      OK
      The voltage and value displayed in the Data List change.
      Result
      Result Proceed to
      OK A
      NG (The voltage changes but the value displayed in the Data List does not change.)
      NG (The voltage does not change.) B

    A

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    B

    REPLACE AIR CONDITIONER PRESSURE SENSOR Click here

  6. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - AIR CONDITIONER PRESSURE SENSOR)


    1. Disconnect the P57 air conditioning amplifier assembly connector.

    2. Disconnect the A39 air conditioner pressure sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P57-3 (SG-7) - A39-1 (-) Always Below 1 Ω
      P57-3 (SG-7) or A39-1 (-) - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - AIR CONDITIONER PRESSURE SENSOR)


    1. Disconnect the P57 air conditioning amplifier assembly connector.

    2. Disconnect the A39 air conditioner pressure sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P57-6 (S5-3) - A39-3 (+) Always Below 1 Ω
      P57-6 (S5-3) - A39-3 (+) - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR