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 Pressure Sensor Circuit

  • Diagnosis condition: engine switch on (IG)

  • Malfunction Status: Refrigerant pressure signal malfunction

  • Detection time: Continuously for 4 seconds or more (Present malfunction)

  • Air conditioner pressure sensor

  • Harness or connector

  • Air conditioning system (leaks, blocked)

  • 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)

  • Air conditioning amplifier assembly

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

  • Refrigerant pressure (overcharged, lack)

 -

WIRING DIAGRAM

B000WITE16
*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.

PROCEDURE


  1. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Air Conditioner > Trouble Codes
      Result
      Result Proceed to
      DTC B14B8 is output A
      DTC B14B8 is not output B

    A

    GO TO DTC B14B8 Click here

    B

  2. CHECK REFRIGERANT SHORTAGE


    1. Prepare the vehicle according to the table below.

      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.

    2. Connect the GTS to the DLC3.

    3. Turn the engine switch on (READY).

    4. Turn the GTS on.

    5. Enter the following menus: Body Electrical / Air Conditioner / Utility / Refrigerant Gas Volume Check.


      Body Electrical > Air Conditioner > Utility
      Tester Display
      Refrigerant Gas Volume Check
      Result
      Result Amount of Refrigerant
      Refrigerant shortage Insufficient or leakage
      Refrigerant correct Correct
      Result
      Result Proceed to
      Insufficient or leakage A
      Correct B

    B

    CHECK REFRIGERANT PRESSURE Click here

    A

  3. REPAIR AIR CONDITIONING SYSTEM LEAK


    1. Identify the area where refrigerant leaks from.


    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 for HFC-134a (R134a): Click here for HFO-1234yf (R1234yf): Click here

  4. CHECK REFRIGERANT PRESSURE


    1. Connect the GTS to the DLC3.

    2. Turn the engine 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.: -0.4566 MPaG

      Max.: 3.2943 MPaG

      		 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.


    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

    OK

    CHECK REFRIGERANT PRESSURE for HFC-134a (R134a): Click here for HFO-1234yf (R1234yf): Click here

    NG

  5. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B000W9GC03
      *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 Engine 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

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


    1. B000W9GC04
      *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

  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
      P57-24 (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

  8. 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. B000V70C02
        *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

        • Engine 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 engine 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.: -0.4566 MPaG

      Max.: 3.2943 MPaG

      		 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

  9. 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

  10. 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