AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System), Diagnostic DTC:B1423

DTC Code DTC Name
B1423 Open in Pressure Sensor Circuit / Abnormal Refrigerant Pressure

DESCRIPTION

This DTC is stored if refrigerant pressure on the high pressure side is extremely low (176 kPa (1.8 kgf/cm2, 26 psi) or less) or extremely high (3025 kPa (30.8 kgf/cm2, 439 psi) or more). The air conditioner pressure sensor, which is installed to the high pressure side pipe to detect refrigerant pressure, sends a refrigerant pressure signal to the air conditioning amplifier assembly. The air conditioning amplifier assembly converts this signal to a pressure value according to the sensor characteristics and uses it to control the compressor.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B1423 Open in Pressure Sensor Circuit / Abnormal Refrigerant Pressure

  • Open or short in air conditioner pressure sensor circuit

  • Refrigerant pressure on high pressure side is extremely low (176 kPa (1.8 kgf/cm2, 26 psi) or less) or extremely high (3025 kPa (30.8 kgf/cm2, 439 psi) or more)

  • Air conditioner pressure sensor

  • Harness or connector

  • Air conditioning amplifier assembly

  • Cooler expansion valve (blocked, stuck)

  • Cooler condenser assembly (blocked, deterioration of cooling capacity due to dirt)

  • Cooler dryer (moisture in the refrigerant cycle cannot be absorbed)

  • Cooling fan system (cooler condenser assembly cannot be cooled down)

  • Air conditioning system (leaks, blocked)

  • Refrigerant volume (excessive, low)

 -

WIRING DIAGRAM

B006ZX4E01
*a Air Conditioner Pressure Sensor
*b Air Conditioning Amplifier Assembly

CAUTION / NOTICE / HINT

Tech Tips

If DTC B1423 and B14B8 are output at the same time, troubleshoot for DTC B14B8 first.

Click here

PROCEDURE


  1. PERFORM REFRIGERANT SHORTAGE CHECK


    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 / Utility / Refrigerant Gas Volume Check.


      Body Electrical > Air Conditioner > Utility
      Tester Display
      Refrigerant Gas Volume Check

    5. Check that the following conditions are met and perform the refrigerant shortage check according to the display on the GTS.

      Measurement Condition:
      Item Condition
      A/C switch On
      Ambient temperature* 0 to 49°C (32 to 120°F)
      Blower speed HI

      *: If the ambient temperature is not within the range shown, do not perform this check.

      Result
      Result Amount of Refrigerant
      Refrigerant correct Correct
      Refrigerant shortage Insufficient
      OK
      "Refrigerant correct" is displayed on the GTS.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR AIR CONDITIONING SYSTEM LEAK Click here

    OK

  2. 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 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 set.

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

    NG

    CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Click here

    OK

  3. CHECK REFRIGERANT HIGH PRESSURE HISTORY


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

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

    4. 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
      Refrigerant High Pressure History Refrigerant high pressure history

      Min.: 0

      Max.: 255

      		 Number of times refrigerant high pressure history stored displayed -

      Body Electrical > Air Conditioner > Data List
      Tester Display
      Refrigerant High Pressure History
      Result
      Result Proceed to
      The value is 0 A
      The value is not 0 B

    A

    INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET Click here

    B

  4. INSPECT COOLING FAN SYSTEM


    1. Check if the cooling fan operates normally.

      for 2AR-FE: Click here

      for A25A-FKS: Click here

      for 2GR-FKS: Click here

      Result
      Proceed to
      OK
      NG

    NG

    GO TO COOLING FAN SYSTEM for 2AR-FE: Click here
    GO TO COOLING FAN SYSTEM for 2GR-FKS: Click here
    GO TO COOLING FAN SYSTEM for A25A-FKS: Click here

    OK

  5. RECOVER REFRIGERANT FROM REFRIGERATION SYSTEM


    1. Recover the refrigerant from the air conditioning system using a refrigerant recovery unit.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  6. CHARGE AIR CONDITIONING SYSTEM WITH REFRIGERANT

    Click here

    Result
    Proceed to
    NEXT

    NEXT

  7. PERFORM REFRIGERANT HIGH PRESSURE HISTORY CLEAR


    1. Clear the refrigerant high pressure history stored in the air conditioning amplifier assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    END

  8. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

    B0070SCC07
    *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 (+) - A18-1 (-) 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

  9. 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

  10. 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

  11. INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)

    B006YDNC30
    *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*

        • *: While sensor voltage is 5 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

  12. 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

  13. 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

  14. REPAIR AIR CONDITIONING SYSTEM LEAK


    1. Identify the area where refrigerant is leaking from.

      Click here

    2. Repair the identified area of the air conditioning system.

    3. Evacuate the air conditioning system.

      Result
      Proceed to
      NEXT

    NEXT

    CHARGE SYSTEM WITH REFRIGERANT Click here