AIR CONDITIONING SYSTEM(for Manual Air Conditioning System), Diagnostic DTC:B1423/23

DTC Code DTC Name
B1423/23 Pressure Sensor Circuit

DESCRIPTION

This DTC is output when refrigerant pressure is extremely low (-0.4566 MPaG (-4.6 kgf/cm2, -66 psi) or less) or extremely high (3.2943 MPaG (33.6 kgf/cm2, 477 psi) or more). The air conditioner pressure sensor, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs the refrigerant pressure signal to the air conditioning amplifier assembly. The air conditioning amplifier assembly converts the signal to pressure according to the sensor characteristics to control the compressor.

Tech Tips

Be sure to check the refrigerant volume first when this DTC is output because this DTC can also be output if there is no refrigerant in the cycle.

DTC Code DTC Detection Condition Trouble Area
B1423/23/23

  • An open or short in the air conditioner pressure sensor circuit

  • Refrigerant pressure on the high pressure side is extremely low (-0.4566 MPaG (-4.6 kgf/cm2, -66 psi) or less) or extremely high (3.2943 MPaG (33.6 kgf/cm2, 477 psi) or more)

  • Air conditioner pressure sensor

  • Harness or connector

  • 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)

  • Condenser fan (condenser cannot be cooled down)

  • Air conditioning system (leaks, blocked)

  • Refrigerant pipe line

  • Air conditioning amplifier assembly

WIRING DIAGRAM

B001YSVE14
*a Air Conditioner Pressure Sensor
*b Air Conditioning Amplifier Assembly

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B001YF2E04
      Text in Illustration
      *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
      A13-3 (+) - Body ground Ignition switch ON 4.4 to 5.5 V

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)


    1. B001XERE03
      Text in Illustration
      *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
      A13-1 (-) - Body ground Always Below 1 Ω

    NG

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

    OK

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


    1. B00203JE01
      Text in Illustration
      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      Remove the air conditioning amplifier assembly with its connectors still connected Click here.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      E81-9 (PRE) - Body ground

      • Ignition switch ON

      • A/C switch off

      		 0.7 to 4.8 V

      Tech Tips

      If the measured voltage is not within the normal range, there may be a malfunction in the air conditioning amplifier assembly, air conditioner pressure sensor, or wire harness. It is also possible that the amount of refrigerant may not be appropriate.


    NG

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

    OK

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


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

      Item Condition
      Engine Speed 1500 rpm
      Vehicle Doors Fully open
      Temperature Setting MAX COLD
      Blower Speed HI
      A/C Switch ON
      R/F 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 4.8 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 problem symptom 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 ambient temperature and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.


      1. B00203JE01
        Text in Illustration
        *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
        B81-9 (PRE) - Body ground

        • Ignition switch ON

        • A/C switch on

        		 0.7 to 4.8 V

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    INSPECT CONDENSER FAN Click here

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


    1. Disconnect the A13 air conditioner pressure sensor connector.

    2. Disconnect the E81 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-3 (+) - E81-30 (S5-3) Always Below 1 Ω
      A13-3 (+) or E81-30 (S5-3) - Body ground Always 10 kΩ or higher

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the A13 air conditioner pressure sensor connector.

    2. Disconnect the E81 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-1 (-) - E81-13 (SG-2) Always Below 1 Ω
      A13-1 (-) or E81-13 (SG-2)- Body ground Always 10 kΩ or higher

    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 A13 air conditioner pressure sensor connector.

    2. Disconnect the E81 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-2 (PR) - E81-9 (PRE) Always Below 1 Ω
      A13-2 (PR) or E81-9 (PRE) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. INSPECT FOR AIR CONDITIONING SYSTEM LEAK


    1. Install the manifold gauge set.

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

    3. Evacuate the air conditioning system and check that vacuum can be maintained in it.

      OK
      Vacuum can be maintained in the air conditioning system.

      Tech Tips

      If vacuum cannot be maintained in the air conditioning system, refrigerant may be leaking from it. In this case, it is necessary to repair or replace the leaking part of the air conditioning system.


    NG

    REPAIR AIR CONDITIONING SYSTEM LEAK Click here

    OK

  9. CHARGE REFRIGERANT


    1. Add an appropriate amount of refrigerant Click here.


    NEXT

  10. RECHECK FOR DTC


    1. Recheck for DTCs when the following conditions are satisfied.

      Item Condition
      Engine Speed 1500 rpm
      Vehicle Doors Fully open
      Temperature Setting MAX COLD
      Blower Speed HI
      A/C Switch ON
      R/F Switch RECIRCULATION
      Interior Temperature 25 to 35°C (77 to 95°F)

      Note

      If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be stored after the air conditioning system operates for 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 ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

      OK
      DTC B1423/23 is not output.

      Note

      If the DTC was output due to an insufficient or excessive amount of refrigerant, the problem may have been solved after performing the previous step. However, the root cause of insufficient refrigerant may be refrigerant leaks. The root cause of excessive refrigerant may be adding refrigerant when the level was insufficient. Therefore, identify and repair the area where refrigerant leaks as necessary.


    OK

    END

    NG

  11. CHECK AIR CONDITIONER PRESSURE SENSOR


    1. B001YROE01
      Text in Illustration
      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      Install the manifold gauge set.

    2. Reconnect the A13 air conditioner pressure sensor connector.

    3. Remove the air conditioning amplifier assembly with its connectors still connected Click here.

    4. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      E81-9 (PRE) - E81-13 (SG-2)

      Refrigerant pressure:

      Normal pressure (less than 3.0732 MPa [31.4 kgf/cm2, 445 psi] and more than 0.1762 MPa [1.8 kgf/cm2, 25 psi])

      		 1.0 to 4.8 V

      Refrigerant pressure:

      Abnormal (less than 0.1762 MPa [1.8 kgf/cm2, 25 psi])

      		 Below 1 V

      Refrigerant pressure:

      Abnormal (more than 3.0732 MPa [31.4 kgf/cm2, 445 psi])

      		 4.8 V or higher

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPLACE AIR CONDITIONER PRESSURE SENSOR Click here

  12. REPAIR AIR CONDITIONING SYSTEM LEAK


    1. Identify the area where refrigerant leaks Click here.

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

    3. Evacuate the air conditioning system.


    NEXT

    CHARGE REFRIGERANT Click here

  13. INSPECT CONDENSER FAN

    Note

    For vehicles without an condenser fan, go to "CHARGE REFRIGERANT".


    1. Inspect that the condenser fan operates normally Click here.


    NG

    REPLACE CONDENSER FAN Click here

    OK

  14. CHARGE REFRIGERANT


    1. Use a refrigerant recovery unit to recover refrigerant.

    2. Evacuate the air conditioning system.

    3. Add an appropriate amount of refrigerant Click here.

      Tech Tips

      If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system will freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for the DTC.


    NEXT

  15. RECHECK FOR DTC


    1. Recheck for DTCs when the following conditions are satisfied.

      Item Condition
      Engine Speed 1500 rpm
      Vehicle Doors Fully open
      Temperature Setting MAX COLD
      Blower Speed HI
      A/C Switch ON
      R/F Switch RECIRCULATION
      Interior Temperature 25 to 35°C (77 to 95°F)

      Note

      If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be stored after the air conditioning system operates for 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 ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

      • If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system will freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for the DTC. If the DTC is not output after this procedure, it indicates that the cooler dryer in the condenser is not able to absorb moisture in the refrigerant cycle. In this case, to complete the repair it is necessary to replace the cooler dryer.

      OK
      DTC B1423/23 is not output.

    OK

    REPLACE COOLER DRYER Click here

    NG

  16. REPLACE COOLER EXPANSION VALVE


    1. Replace the cooler expansion valve with a normal one.


      Tech Tips

      Replace the cooler expansion valve with a normal one because the cooler expansion valve is either stuck or clogged.


    NEXT

  17. CHARGE REFRIGERANT


    1. Add an appropriate amount of refrigerant Click here.


    NEXT

  18. RECHECK FOR DTC


    1. Recheck for DTCs when the following conditions are satisfied.

      Item Condition
      Engine Speed 1500 rpm
      Vehicle Doors Fully open
      Temperature Setting MAX COLD
      Blower Speed HI
      A/C Switch ON
      R/F Switch RECIRCULATION
      Interior Temperature 25 to 35°C (77 to 95°F)

      Note

      If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be stored after the air conditioning system operates for 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 ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

      • If refrigerant pressure is not normal after replacing the expansion valve with a normal one, the condenser or pipes may be clogged due to dirt, dust or other contaminants. In this case, clean or replace the condenser or pipes.

      OK
      DTC B1423/23 is not output.

    OK

    END

    NG

    REPLACE COOLER CONDENSER ASSEMBLY Click here