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

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DTC Code DTC Name
B1423 Pressure Sensor Circuit
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DESCRIPTION

This DTC is stored when refrigerant pressure is extremely low (0.176 MPa [1.8 kgf/cm2, 26 psi] or less) or extremely high (3.03 MPa [30.9 kgf/cm2, 441 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. DTC Detection Condition Trouble Area
B1423

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

  • Amount of Refrigerant (too much or Insufficient)

  • Cooling fan system
Table 1. *a Air Conditioner Pressure Sensor *b Air Conditioning Amplifier Assembly
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WIRING DIAGRAM

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PROCEDURE


  1. Click here

    CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. A01VJRGE01

      Disconnect the A23 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
      A23-3 (+) - Body ground Ignition switch ON 4.75 to 5.25 V
      Table 2. Text in Illustration
      *a

      Front view of wire harness connector

      (to Air Conditioner Pressure Sensor)

  2. Click here

    CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)


    1. A01VJ7WE01

      Disconnect the A23 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
      A23-1 (-) - Body ground Always Below 1 Ω
      Table 3. Text in Illustration
      *a

      Front view of wire harness connector

      (to Air Conditioner Pressure Sensor)

  3. Click here

    CHECK AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)


    1. Reconnect the air conditioner pressure sensor connector.

    2. A01VGQZE03

      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
      F41-7 (PRE) - Body ground

      Ignition switch ON

      A/C switch off

      		 0.70 to 4.69 V
      Table 4. Text in Illustration
      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)
      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.


  4. Click here

    CHECK AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)


    1. A01VGQZE03

      Measure the voltage when the following conditions are met.

      Table 5. Measurement Condition
      Item Condition
      Engine Speed 1500 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
        F41-7 (PRE) - Body ground

        Ignition switch ON

        A/C switch on

        		 0.70 to 4.69 V
        Table 6. Text in Illustration
        *a

        Component with harness connected

        (Air Conditioning Amplifier Assembly)
        Table 7. Result
        Result Proceed to
        OK (When troubleshooting according to the DTC) A
        OK (When troubleshooting according to Problem Symptoms Table) B
        NG C

  5. Click here

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


    1. Disconnect the A23 air conditioner pressure sensor connector.

    2. Disconnect the F41 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
      A23-3 (+) - F41-24 (S5- 3) Always Below 1 Ω
      A23-3 (+) - Body ground Always 10 kΩ or higher

    • OK

      REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. Click here

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


    1. Disconnect the A23 air conditioner pressure sensor connector.

    2. Disconnect the F41 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
      A23-1 (-) - F41-5 (SG-2) Always Below 1 Ω
      A23-1 (-) - Body ground Always 10 kΩ or higher

    • OK

      REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. Click here

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


    1. Disconnect the A23 air conditioner pressure sensor connector.

    2. Disconnect the F41 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
      A23-2 (PR) - F41-7 (PRE) Always Below 1 Ω
      A23-2 (PR) - Body ground Always 10 kΩ or higher

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. Click here

    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.


  9. Click here

    CHARGE REFRIGERANT


    1. Add an appropriate amount of refrigerant.



  10. Click here

    CHECK FOR DTC


    1. Check for DTCs when the following conditions are met (Click here).

      Table 8. Measurement Condition
      Item Condition
      Engine Speed 1500 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.


  11. Click here

    INSPECT AIR CONDITIONER PRESSURE SENSOR


    1. Inspect the air conditioner pressure sensor.



  12. Click here

    REPAIR AIR CONDITIONING SYSTEM LEAK


    1. Identify the area where refrigerant leaks.


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

    3. Evacuate the air conditioning system.

      Table 9. Result
      Result Proceed to
      NEXT*1 A
      NEXT*2 B

      • *1: for HFC-134a(R134a)

      • *2: for HFO-1234yf(R1234yf)


  13. Click here

    CHECK COOLING FAN SYSTEM


    1. Check that the cooling fan(s) operates normally.


      • for 1KR-FE: Refer to Cooling Fan Circuit (Click here).

      • for 1NR-FE: Refer to Cooling Fan Circuit (Click here).

      • for 1ND-FE: Refer to Cooling Fan Circuit (Click here).


  14. Click here

    CHARGE REFRIGERANT


    1. Use a refrigerant recovery unit to recover refrigerant.

    2. Evacuate the air conditioning system.

    3. Add an appropriate amount of refrigerant.


      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.


  15. Click here

    CHECK FOR DTC


    1. Check for DTCs when the following conditions are met (Click here).

      Table 10. Measurement Condition
      Item Condition
      Engine Speed 1500 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 output
      Table 11. Result
      Result Proceed to
      OK A
      NG (for 1ND-TV) B
      NG (except 1ND-TV) C

  16. Click here

    REPLACE COOLER EXPANSION VALVE


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

      Tip:

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


  17. Click here

    CHARGE REFRIGERANT


    1. Add an appropriate amount of refrigerant.



  18. Click here

    CHECK FOR DTC


    1. Check for DTCs when the following conditions are met (Click here).

      Table 12. Measurement Condition
      Item Condition
      Engine Speed 1500 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
      Table 13. Result
      Result Proceed to
      OK A
      NG (for 1ND-TV) B
      NG (except 1ND-TV) C

    • A

      END

    • B

      CLEAN OR REPLACE COOLER CONDENSER ASSEMBLY WITH RECEIVER OR PIPES (Click here)

    • C

      CLEAN OR REPLACE COOLER CONDENSER ASSEMBLY WITH RECEIVER OR PIPES (Click here)

  19. Click here

    REPLACE AIR CONDITIONER PRESSURE SENSOR


    1. Replace the air conditioner pressure sensor.


  20. Click here

    CHECK FOR DTC


    1. Check for DTCs when the following conditions are met (Click here).

      Table 14. Measurement Condition
      Item Condition
      Engine Speed 1500 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

    • OK

      END

    • NG

      REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)