AIR CONDITIONING SYSTEM(for Automatic 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.

If the amount of refrigerant is insufficient, the A/C switch indicator will turn off and the air conditioning system will stop operating.

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

The following condition is detected in the normal operation refrigerant shortage check:

Amount of refrigerant is insufficient

  • Refrigerant line

  • Cooler expansion valve

  • Air conditioning amplifier assembly

  • Harness or connector

  • Air conditioner pressure sensor

Memorized

(10 min. or more)*

WIRING DIAGRAM

B006ZX4E01
*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 ignition switch to ON.

    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 (gauge)

      Max.: 3294.3 kPaG (gauge)

      		 Actual refrigerant pressure displayed

      • Refrigerant line (gas leak etc.)

      • Air conditioner pressure sensor circuit malfunction

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

    6. Install a manifold gauge set.

      Click here

    7. Read the manifold gauge set with the following conditions 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 30 to 35°C (86 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 set.

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

    OK

    INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET Click here

    NG

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

    B0070SCC05
    *a

    Front view of wire harness connector

    (to Air Conditioner Pressure Sensor)

    1. Disconnect the A18 air conditioner pressure sensor connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A18-3 (+) - Body ground Ignition switch ON 4.75 to 5.25 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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

    B0070SCC06
    *a

    Front view of wire harness connector

    (to Air Conditioner Pressure Sensor)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A18-1 (-) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Disconnect the K55 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A18-2 (PR) - K55-24 (PRE) Always Below 1 Ω
      A18-2 (PR) or K55-24 (PRE) - 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 CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)

    B006YDNC29
    *a

    Component with harness connected

    (Air Conditioning Amplifier Assembly)

    1. Measure the voltage with the following conditions 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), a fail-safe function will stop compressor operation. In this case, make sure to measure the voltage before the fail-safe function operates.

      • 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 ambient air temperature is low (below -1.5°C (29.3°F)), the compressor with pulley will be stopped, due to inputs of the thermistor assembly and No. 1 cooler thermistor, to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.


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

        Standard Voltage
        Tester Connection Condition Specified Condition
        K55-24 (PRE) - Body ground

        Ignition switch ON

        (A/C switch: On)

        		 0.74 to 4.61 V

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    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 (gauge)

      Max.: 3294.3 kPaG (gauge)

      		 Actual refrigerant pressure displayed

      • Refrigerant line (gas leak etc.)

      • Air conditioner pressure sensor circuit 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 CONDITIONER PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the K55 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A18-1 (-) - K55-3 (SG-4) Always Below 1 Ω
      A18-1 (-) or K55-3 (SG-4) - 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 CONDITIONER PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the K55 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A18-3 (+) - K55-6 (S5-3) Always Below 1 Ω
      A18-3 (+) or K55-6 (S5-3) - 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