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

DTC Code DTC Name
B1423 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 more). The air conditioning 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 can also be stored if there is no refrigerant in the cycle.

DTC Code

DTC Detection Condition

Trouble Area

B1423

Either condition is met:

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

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

  • Air conditioning pressure sensor

  • Harness or connector

  • Cooler expansion valve

  • Condenser assembly with receiver

  • Cooler dryer

  • Refrigerant pipe line

  • Air conditioning amplifier assembly

WIRING DIAGRAM

E156766E42

PROCEDURE

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

    1. U123693E01

      Disconnect the A16 sensor connector.

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      A16-3 (+) - Body ground

      Ignition switch ON

      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

      A16-1 (-) - Body ground

      Always

      Below 1 Ω
    Table 1. Text in Illustration

    *1

    Front view of wire harness connector

    (to Air Conditioning Pressure Sensor)

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

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

    1. U124084E01

      Reconnect the A16 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

      H118-7 (PRE) - Body ground

      Ignition switch ON

      A/C switch off

      0.70 to 4.61 V
      Table 2. Text in Illustration

      *1

      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 conditioning pressure sensor or wire harness. It is also possible that the amount of refrigerant may not be appropriate.

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

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

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

      Table 3. 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 (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.

      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.

    2. U124084E01

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      H118-7 (PRE) - Body ground

      Ignition switch ON

      A/C switch on

      0.70 to 4.61 V
      Table 4. Text in Illustration

      *1

      Component with harness connected

      (Air Conditioning Amplifier Assembly)
      Table 5. Result

      Result

      Proceed to

      OK (When troubleshooting according to Problem Symptoms Table)

      A

      OK (When troubleshooting according to the DTC)

      B

      NG

      C

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

    (Click here)

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    (Click here)

    CHARGE REFRIGERANTClick here

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

    1. U124096E02

      Disconnect the H118 amplifier connector.

    2. Disconnect the A16 sensor connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A16-1 (-) - H118-5 (SG-2)

      Always

      Below 1 Ω

      A16-3 (+) - H118-24 (S5-3)

      Always

      Below 1 Ω

      H118-5 (SG-2) - Body ground

      Always

      10 kΩ or higher

      H118-24 (S5-3) - Body ground

      Always

      10 kΩ or higher
      Table 6. Text in Illustration

      *1

      Front view of wire harness connector

      (to Air Conditioning Pressure Sensor)

      *2

      Rear view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    (Click here)

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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

    1. U124097E02

      Disconnect the H118 amplifier connector.

    2. Disconnect the A16 sensor connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A16-2 (PR) - H118-7 (PRE)

      Always

      Below 1 Ω

      H118-7 (PRE) - Body ground

      Always

      10 kΩ or higher
      Table 7. Text in Illustration

      *1

      Front view of wire harness connector

      (to Air Conditioning Pressure Sensor)

      *2

      Rear view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. 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.

    REPAIR AIR CONDITIONING SYSTEM LEAKClick here

  7. CHARGE REFRIGERANT

    1. Add an appropriate amount of refrigerant.

  8. CHECK FOR DTC

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

      Table 8. 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 leakage as necessary. The root cause of excessive refrigerant may be adding too much refrigerant.

    END (COOLER EXPANSION VALVE IS FAULTY)

  9. CHECK AIR CONDITIONING PRESSURE SENSOR

    1. Install a manifold gauge set.

      U124098E02
      Table 9. Text in Illustration

      *1

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      -

      -

    2. Reconnect the A16 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

      Switch Condition

      Specified Condition

      H118-7 (PRE) - H118-5 (SG-2)

      • Ignition switch ON

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

      0.70 to 4.61 V

      • Ignition switch ON

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

      Below 0.70 V

      • Ignition switch ON

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

      4.61 V or higher

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    (Click here)

    REPLACE AIR CONDITIONING PRESSURE SENSOR

    (Click here)

  10. 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.

    CHARGE REFRIGERANT

    (Click here)

  11. 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.

  12. CHECK FOR DTC

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

      Table 10. 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 condenser assembly with receiver 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.

      Table 11. Result

      Result

      Proceed to

      DTC B1423 is output

      A

      DTC B1423 is not output (for 1WW)

      B

      DTC B1423 is not output (except 1WW)

      C

    REPLACE COOLER DRYER

    (Click here)

    REPLACE COOLER DRYER

    (Click here)

  13. 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.

  14. CHARGE REFRIGERANT

    1. Add an appropriate amount of refrigerant.

  15. CHECK FOR DTC

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

      Table 12. 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 condenser assembly with receiver or pipes may be clogged due to dirt, dust or other contaminants. In this case, clean or replace the condenser assembly with receiver or pipes.

      Table 13. Result

      Result

      Proceed to

      DTC B1423 is not output

      A

      DTC B1423 is output (for 1WW)

      B

      DTC B1423 is output (except 1WW)

      C

    END (COOLER EXPANSION VALVE IS FAULTY)

    CLEAN OR REPLACE CONDENSER ASSEMBLY WITH RECEIVER OR PIPES

    (Click here)

    CLEAN OR REPLACE CONDENSER ASSEMBLY WITH RECEIVER OR PIPES

    (Click here)