AIR CONDITIONING SYSTEM, Diagnostic DTC:B1423/23

DTC Code DTC Name
B1423/23 Pressure Sensor Circuit

DESCRIPTION

This DTC is stored when refrigerant pressure is extremely low (0.176 MPa [1.8 kgf/cm2, 25.5 psi] or less) or extremely high (3.025 MPa [30.9 kgf/cm2, 438.6 psi] or higher). 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 a pressure value according to the sensor characteristics to control the compressor.

Tip:

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

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

Note

B1423/23

Pressure Sensor Circuit

Either condition is met:

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

  • Refrigerant pressure on the high pressure side is extremely low or extremely high.

  • Air conditioner pressure sensor

  • Harness or connector

  • Cooler expansion valve

  • Cooler condenser assembly

  • Cooler dryer

  • Refrigerant pipe line

  • Air conditioning amplifier assembly

Stored

(4 seconds or more)

-

WIRING DIAGRAM

E156766E23

PROCEDURE

  1. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - BATTERY AND BODY GROUND)

    1. E167097C01

      *a

      Front view of wire harness connector

      (to Air Conditioning Pressure Sensor)

      Disconnect the A2 sensor connector.

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      A2-3 (+) - Body ground

      Engine switch on (IG)

      4.75 to 5.25 V

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A2-1 (-) - Body ground

      Always

      Below 1 Ω

    Result

    Result

    OK

    NG
    NG

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

    OK

  2. CHECK AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)

    1. E197830C01

      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      Reconnect the A2 sensor connector.

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

      Click here

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      G13-9 (PRE) - Body ground

      Engine switch on (IG)A/C switch off

      0.63 to 4.72 V
    Tip:

    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.

    Result

    Result

    OK

    NG
    NG

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

    OK

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

    1. E197830C02

      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      Measure the voltage when the following conditions are met.

      Measurement Condition

      Item

      Condition

      Engine Speed

      2000 rpm

      Vehicle Doors

      Fully open

      Temperature Setting

      MAX COOL

      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 (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.

      Tip:

      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 evaporator temperature sensor 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

        Switch Condition

        Specified Condition

        G13-9 (PRE) - Body ground

        Engine switch on (IG)A/C switch on

        0.63 to 4.72 V

    Result

    Result

    Proceed to

    OK (When troubleshooting according to problem symptoms table)

    A

    OK (When troubleshooting according to the DTC)

    B

    NG

    C
    A

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

    Click here

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    Click here

    C

  4. 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

      Tip:

      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 then check for the DTC.

    Result

    Result

    NEXT
    NEXT

  5. CHECK FOR DTC

    1. Check for DTCs when the following conditions are met

      Click here

      Body Electrical > Air Conditioner > Trouble Codes

      Measurement Condition

      Item

      Condition

      Engine Speed

      2000 rpm

      Vehicle Doors

      Fully open

      Temperature Setting

      MAX COOL

      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, a DTC will be stored. Therefore, it is necessary to check for DTCs after a certain amount of time (approximately 10 minutes) has passed because the DTC may be stored after the air conditioning system operates for a while.

      Tip:

      • 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 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 cooler condenser assembly 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 is not output.

    Result

    Result

    OK

    NG
    OK

    REPLACE COOLER DRYER

    Click here

    NG

  6. REPLACE COOLER EXPANSION VALVE

    1. Replace the cooler expansion valve with a new or normally functioning one

      Click here

      Tip:

      Replace the cooler expansion valve with a new or normally functioning one because the cooler expansion valve is either stuck or clogged.

    Result

    Result

    NEXT
    NEXT

  7. CHARGE REFRIGERANT

    1. Add an appropriate amount of refrigerant

      Click here

    Result

    Result

    NEXT
    NEXT

  8. CHECK FOR DTC

    1. Check for DTCs when the following conditions are met.

      Body Electrical > Air Conditioner > Trouble Codes

      Measurement Condition

      Item

      Condition

      Engine Speed

      2000 rpm

      Vehicle Doors

      Fully open

      Temperature Setting

      MAX COOL

      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, a DTC will be stored. Therefore, it is necessary to check for DTCs after a certain amount of time (approximately 10 minutes) has passed because the DTC may be stored after the air conditioning system operates for a while.

      Tip:

      • 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 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 new or normally functioning one, the cooler condenser assembly or pipes may be clogged due to dirt, dust or other contaminants. In this case, clean or replace the cooler condenser assembly or pipes.

      OK

      DTC B1423 is not output.

    Result

    Result

    OK

    NG
    OK

    END (COOLER EXPANSION VALVE IS FAULTY)

    NG

    CLEAN OR REPLACE COOLER CONDENSER ASSEMBLY OR PIPES

    Click here

  9. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)

    1. Disconnect the G13 amplifier connector.

    2. Disconnect the A2 sensor connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A2-2 (PR) - G13-9 (PRE)

      Always

      Below 1 Ω

      G13-9 (PRE) - Body ground

      Always

      10 kΩ or higher

    Result

    Result

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK FOR AIR CONDITIONING SYSTEM LEAK

    1. Install a 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.

      Tip:

      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.

    Result

    Result

    OK

    NG
    NG

    REPAIR AIR CONDITIONING SYSTEM LEAKClick here

    OK

  11. CHARGE REFRIGERANT

    1. Add an appropriate amount of refrigerant

      Click here

    Result

    Result

    NEXT
    NEXT

  12. CHECK FOR DTC

    1. Check for DTCs when the following conditions are met

      Click here

      Body Electrical > Air Conditioner > Trouble Codes

      Measurement Condition

      Item

      Condition

      Engine Speed

      2000 rpm

      Vehicle Doors

      Fully open

      Temperature Setting

      MAX COOL

      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, a DTC will be stored. Therefore, it is necessary to check for DTCs after a certain amount of time (approximately 10 minutes) has passed because the DTC may be stored after the air conditioning system operates for a while.

      Tip:

      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 evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

      OK

      DTC B1423 is not output.

      Note:

      If the DTC was stored 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 leakage. Therefore, identify and repair the area where refrigerant leaks as necessary. The root cause of excessive refrigerant may be adding too much refrigerant.

    Result

    Result

    OK

    NG
    OK

    END (AMOUNT OF REFRIGERANT IS FAULTY)

    NG

    CHECK AIR CONDITIONER PRESSURE SENSORClick here

  13. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)

    1. Disconnect the G13 amplifier connector.

    2. Disconnect the A2 sensor connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A2-1 (-) - G13-13 (SG-2)

      Always

      Below 1 Ω

      A2-3 (+) - G13-10 (S5-3)

      Always

      Below 1 Ω

      G13-13 (SG-2) - Body ground

      Always

      10 kΩ or higher

      G13-10 (S5-3) - Body ground

      Always

      10 kΩ or higher

    Result

    Result

    OK

    NG
    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  14. CHECK AIR CONDITIONER PRESSURE SENSOR

    1. E197830C03

      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      Install a manifold gauge set.

    2. Reconnect the A2 sensor connector.

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

      Click here

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      G13-9 (PRE) - G13-13 (SG-2)

      • Engine switch on (IG)

      • Refrigerant pressure normal (below 3.025 MPa [30.9 kgf/cm2, 438.6 psi] and higher than 0.176 MPa [1.8 kgf/cm2, 25.5 psi])

      0.63 to 4.72 V

      • Engine switch on (IG)

      • Refrigerant pressure abnormal (below 0.176 MPa [1.8 kgf/cm2, 25.5 psi])

      Below 0.63 V

      • Engine switch on (IG)

      • Refrigerant pressure abnormal (higher than 3.025 MPa [30.9 kgf/cm2, 438.6 psi])

      4.72 V or higher

    Result

    Result

    OK

    NG
    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    Click here

    NG

    REPLACE AIR CONDITIONER PRESSURE SENSOR

    Click here

  15. 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.

    Result

    Result

    NEXT
    NEXT

    CHARGE REFRIGERANT

    Click here