AIR CONDITIONING SYSTEM, Diagnostic DTC:B1423/23

DTC Code DTC Name
B1423/23 Pressure Sensor Circuit

DESCRIPTION

This DTC is stored if refrigerant pressure on the high pressure side is extremely low (0.19 MPa [2.0 kgf/cm2, 28 psi] or less) or extremely high (3.14 MPa [32.0 kgf/cm2, 455 psi] or more). The air conditioner pressure sensor, which is installed on the pipe on the high pressure side 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 Code DTC Detection Condition Trouble Area
B1423/23

  • Open or short in air conditioner pressure sensor circuit

  • Refrigerant pressure on the high pressure side is extremely low (0.19 MPa [2.0 kgf/cm2, 28 psi) or less] or extremely high (3.14 MPa [32.0 kgf/cm2, 455 psi] or more).

  • Air conditioner pressure sensor

  • Harness or connector

  • Air conditioning amplifier assembly

  • Cooler expansion valve (blocked, stuck)

  • Cooler dryer (moisture in the refrigerant cycle cannot be absorbed)

  • Cooler condenser assembly (blocked, deterioration of cooling capacity due to dirt)

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

  • Refrigerant

WIRING DIAGRAM

A01FRIEE22

INSPECTION PROCEDURE

Note


  • This DTC is stored when there is no refrigerant in the system, when DTC B1423, B14B8 and B1479 are output simultaneously, perform troubleshooting for DTC B14B8 first.

  • When the auxiliary battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization Click here.

  • Before disconnecting the cable form the negative (-) battery terminal or replacing the air conditioning amplifier assembly, record the last operation state of the air conditioning for each transmitter. After replacement, it is necessary to perform memory registration for each transmitter Click here.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. A01FSESE20
      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
      B7-3 (+) - Body ground Power switch on (IG) 4.75 to 5.25 V

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)


    1. A01FSESE21
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Air Conditioner Pressure Sensor)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B7-1 (-) - Body ground Always Below 1 Ω

    NG

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

    OK

  3. CHECK AIR CONDITIONER PRESSURE SENSOR


    1. Reconnect the B7 air conditioner pressure sensor connector.

    2. A01FV8EE10
      Text in Illustration
      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      Remove the air conditioning amplifier assembly with 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
      N157-9 (PRE) - Body ground Power switch on (IG) 0.63 to 4.73 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 amount of refrigerant may not be appropriate.


    NG

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

    OK

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


    1. Turn the power switch on (Ready).

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

      Item Condition
      Vehicle Doors Fully open
      Temperature Setting LO
      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 sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.


      1. A01FV8EE10
        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 Condition Specified Condition
        N157-9 (PRE) - Body ground Conditions in "Measurement Condition" chart above are met 0.63 to 4.73 V
        Result
        Result Proceed to
        OK (When troubleshooting according to the DTC) A
        OK (When troubleshooting according to Problem Symptoms Table) B
        NG C

    B

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    CHECK COOLING FAN SYSTEM Click here

    A

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

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


    1. Disconnect the N157 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B7-3 (+) - N157-13 (S5-3) Always Below 1 Ω
      N157-13 (S5-3) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

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


    1. Disconnect the N157 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B7-1 (-) - N157-32 (SG-2) Always Below 1 Ω
      N157-32 (SG-2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

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


    1. Disconnect the N157 air conditioning amplifier assembly connector.

    2. Disconnect the B7 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
      B7-2 (PR) - N157-9 (PRE) Always Below 1 Ω
      N157-9 (PRE) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK 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 SYSTEM WITH REFRIGERANT


    1. Use a refrigerant recovery unit to recover refrigerant.

    2. Evacuate the air conditioning system.

    3. Add an appropriate amount of refrigerant.


      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 DTCs.


    NEXT

  10. RECHECK FOR DTC


    1. Turn the power switch on (Ready).

    2. Recheck for DTCs when the following conditions are satisfied Click here.

      Item Condition
      Vehicle Doors Fully open
      Temperature Setting LO
      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 set. It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the air conditioning 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 set 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 from as necessary.


    NG

    CHECK AIR CONDITIONER PRESSURE SENSOR Click here

    OK

    END (AMOUNT OF REFRIGERANT WAS DEFECTIVE)

  11. CHECK AIR CONDITIONER PRESSURE SENSOR


    1. Install the manifold gauge set.

    2. Reconnect the air conditioner pressure sensor connector.

    3. A01FV8EE10
      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
      N157-9 (PRE) - Body ground

      Power switch on (Ready)

      Blower switch: Lo

      A/C switch: on (magnet clutch on)

      		 0.63 to 4.73 V

    NG

    REPLACE AIR CONDITIONER PRESSURE SENSOR Click here

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

  12. 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
      Result Proceed to
      for HFC-134a (R134a) A
      for HFO-1234yf (R1234yf) B

    B

    CHARGE SYSTEM WITH REFRIGERANT Click here

    A

    CHARGE SYSTEM WITH REFRIGERANT Click here

  13. CHECK COOLING FAN SYSTEM


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


    NG

    GO TO COOLING FAN SYSTEM Click here

    OK

  14. CHARGE SYSTEM WITH REFRIGERANT


    1. Use a refrigerant recovery unit to recover refrigerant.

    2. Evacuate the air conditioning system.

    3. Add an appropriate amount of refrigerant.


      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 DTCs.


    NEXT

  15. RECHECK FOR DTC


    1. Turn the power switch on (Ready).

    2. Recheck for DTCs when the following conditions are satisfied Click here.

      Item Condition
      Vehicle Doors Fully open
      Temperature Setting LO
      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 set. It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the air conditioning 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 DTCs. If the DTC is not output after this work, it indicates that the cooler dryer in the condenser is not able to absorb moisture in the refrigerant cycle. It is necessary to replace the cooler dryer in order to complete the repair.

      OK
      DTC B1423/23 is not output

    NG

    REPLACE COOLER EXPANSION VALVE Click here

    OK

    REPLACE COOLER CONDENSER ASSEMBLY Click here

  16. REPLACE COOLER EXPANSION VALVE


    1. Replace the cooler expansion valve with a new one Click here.

      Tech Tips

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


    NEXT

  17. CHARGE SYSTEM WITH REFRIGERANT


    1. Use a refrigerant recovery unit to recover refrigerant.

    2. Evacuate the air conditioning system.

    3. Add an appropriate amount of refrigerant.


      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 DTCs.


    NEXT

  18. RECHECK FOR DTC


    1. Turn the power switch on (Ready).

    2. Recheck for DTCs when the following conditions are satisfied Click here.

      Item Condition
      Vehicle Doors Fully open
      Temperature Setting LO
      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 set. It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the air conditioning 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 foreign matter. In this case, clean or replace the condenser or pipes.

      OK
      DTC B1423/23 is not output

    NG

    CLEAN OR REPLACE CONDENSER OR PIPE

    OK

    END (COOLER EXPANSION VALVE WAS DEFECTIVE)