DTC    B1423    Pressure Sensor Circuit

for Preparation Click here


DESCRIPTION

This DTC is stored when refrigerant pressure is extremely low (0.1762 MPa (1.8 kgf/cm2, 25 psi) or less) or extremely high (3.0254 MPa (30.9 kgf/cm2, 439 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. The air conditioning amplifier converts the signal to pressure according to the sensor characteristics to control the compressor.

HINT:
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 No.
DTC Detection Condition
Trouble Area
B1423
  1. An open or short in the air conditioner pressure sensor circuit.
  2. Refrigerant pressure on the high pressure side is extremely low or extremely high.
  1. Air conditioner pressure sensor
  2. Harness and connector
  3. Expansion valve (blocked, stuck)
  4. Condenser (blocked, deterioration of cooling capacity due to dirt)
  5. Cooler dryer (moisture in refrigerant cycle cannot be absorbed)
  6. Condenser fan (condenser cannot be cooled down)
  7. Air conditioning system (leaks, blocked)
  8. Refrigerant pipe line
  9. Air conditioning amplifier

WIRING DIAGRAM


E156766E10


INSPECTION PROCEDURE

1.CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)
E163388E03

  1. Disconnect the A26 air conditioner pressure sensor connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A26-3 (+) - Body ground
    		Ignition switch ON
    		4.75 to 5.25 V

Text in Illustration 
*1
Front view of wire harness connector
(to Air Conditioner Pressure Sensor)


NG
Go to step 5
OK


2.CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)
E163388E04

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A26-1 (-) - Body ground
    		Always
    		Below 1 Ω

  1. Reconnect the A26 air conditioner pressure sensor connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Air Conditioner Pressure Sensor)


NG
Go to step 6
OK


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


    E177747E01

  1. Remove the air conditioning amplifier with its connectors still connected (Click here).

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    D16-12 (PRE) - Body ground
    		Ignition switch ON
    A/C switch off
    		0.70 to 4.69 V

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

Text in Illustration 
*1
Component with harness connected
(Air Conditioning Amplifier)


NG
Go to step 7
OK


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


  1. Measure the voltage when the following conditions are satisfied.
    Measurement Condition 
    Item
    		Condition
    Engine Speed
    		2000 rpm
    Vehicle Doors
    		Fully open
    Temperature Setting
    		Lo
    Blower Speed
    		Hi
    A/C Switch
    		On
    Air inlet control Switch
    		Recirculation
    Interior Temperature
    		25 to 35°C (77 to 95°F)

    NOTICE:
    1. If refrigerant pressure on the high pressure side becomes extremely high during the inspection (if the voltage exceeds 4.84 V), the fail-safe function stops compressor operation. Therefore, measure the voltage before the fail-safe operation.
    2. 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.

    HINT:
    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 (thermistor assembly) and the front evaporator temperature sensor (No. 1 cooler thermistor) to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.



      E177747E01

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

      Standard Voltage:
      Tester Connection
      		Switch Condition
      		Specified Condition
      D16-12 (PRE) - Body ground
      		Ignition switch ON
      A/C switch off
      		0.70 to 4.69 V

      Result 
      Result
      		Proceed to
      OK (When troubleshooting according to DTC output)
      		A
      OK (When troubleshooting according to Problem Symptoms Table)
      		B
      NG
      		C

Text in Illustration 
*1
Component with harness connected
(Air Conditioning Amplifier)


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

C
Go to step 13
A

REPLACE AIR CONDITIONING AMPLIFIER (Click here)  

5.CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)
E176775E02

  1. Disconnect the D16 air conditioning amplifier connector.

  1. Disconnect the A26 air conditioner pressure sensor connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A26-3 (+) - D16-7 (S5-3)
    		Always
    		Below 1 Ω
    D16-7 (S5-3) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the air conditioning amplifier connector.

  1. Disconnect the air conditioner pressure sensor connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Air Conditioner Pressure Sensor)
*2
Front view of wire harness connector
(to Air Conditioning Amplifier)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER (Click here)  

6.CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)
E176775E03

  1. Disconnect the D16 air conditioning amplifier connector.

  1. Disconnect the A26 air conditioner pressure sensor connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A26-1 (-) - D16-23 (SG-1)
    		Always
    		Below 1 Ω
    D16-23 (SG-1) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the air conditioning amplifier connector.

  1. Reconnect the air conditioner pressure sensor connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Air Conditioner Pressure Sensor)
*2
Front view of wire harness connector
(to Air Conditioning Amplifier)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER (Click here)  

7.CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)
E176775E01

  1. Disconnect the D16 air conditioning amplifier connector.

  1. Disconnect the A26 air conditioner pressure sensor connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A26-2 (PR) - D16-12 (PRE)
    		Always
    		Below 1 Ω
    D16-12 (PRE) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the air conditioning amplifier connector.

  1. Reconnect the air conditioner pressure sensor connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Air Conditioner Pressure Sensor)
*2
Front view of wire harness connector
(to Air Conditioning Amplifier)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


8.CHECK FOR AIR CONDITIONING SYSTEM LEAK

  1. Install the manifold gauge set.

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

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

    OK:
    Vacuum can be maintained in the air conditioning system.

    HINT:
    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
Go to step 12
OK


9.CHARGE REFRIGERANT

  1. Add an appropriate amount of refrigerant (Click here).


NEXT


10.RECHECK DTC

  1. Recheck for the DTC when the following conditions are satisfied.
    Measurement Condition 
    Item
    		Condition
    Engine Speed
    		2000 rpm
    Vehicle Doors
    		Fully open
    Temperature Setting
    		Lo
    Blower Speed
    		Hi
    A/C Switch
    		On
    Air inlet control Switch
    		Recirculation
    Interior Temperature
    		25 to 35°C (77 to 95°F)

    NOTICE:
    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.

    HINT:
    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 (thermistor assembly) and the front evaporator temperature sensor (No. 1 cooler thermistor) to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

    OK:
    DTC B1423 is not output.

    NOTICE:
    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 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.



NG
Go to step 11
OK

END 

11.CHECK AIR CONDITIONER PRESSURE SENSOR
E177749E01

  1. Install the manifold gauge set.

  1. Reconnect the A26 air conditioner pressure sensor connector.

  1. Remove the air conditioning amplifier with its connectors still connected (Click here).

  1. Turn the ignition switch to ON.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    D16-12 (PRE) - D16-23 (SG-1)
    		Refrigerant pressure:
    Normal pressure (less than 3.0254 MPa [30.9 kgf/cm2, 439 psi] and more than 0.1762 MPa [1.8 kgf/cm2, 26 psi])
    		0.70 to 4.69 V
    Refrigerant pressure:
    Abnormal (less than 0.1762 MPa [1.8 kgf/cm2, 26 psi])
    		Below 0.7 V
    Refrigerant pressure:
    Abnormal (more than 3.0254 MPa [30.9 kgf/cm2, 439 psi])
    		4.69 V or higher



NG
REPLACE AIR CONDITIONER PRESSURE SENSOR (Click here)
OK

REPLACE AIR CONDITIONING AMPLIFIER (Click here)  

12.REPAIR AIR CONDITIONING SYSTEM LEAK

  1. Identify the area where refrigerant leaks (Click here).

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

  1. Evacuate the air conditioning system.


NEXT

CHARGE REFRIGERANT (Click here)  

13.INSPECT COOLING FAN SYSTEM

  1. Inspect that the cooling fan operates normally (Click here(for 1KR-FE)) (Click here(for 1ND-TV)).

Result 
Result
Proceed to
OK
A
NG (for 1KR-FE)
B
NG (for 1ND-TV)
C


B
REPAIR COOLING FAN SYSTEM (Click here)

C
REPAIR COOLING FAN SYSTEM (Click here)
A


14.CHARGE REFRIGERANT

  1. Use a refrigerant recovery unit to recover refrigerant.

  1. Evacuate the air conditioning system.

  1. Add an appropriate amount of refrigerant (Click here).

    HINT:
    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 DTC

  1. Recheck for the DTC when the following conditions are satisfied.
    Measurement Condition 
    Item
    		Condition
    Engine Speed
    		2000 rpm
    Vehicle Doors
    		Fully open
    Temperature Setting
    		Lo
    Blower Speed
    		Hi
    A/C Switch
    		On
    Air inlet control Switch
    		Recirculation
    Interior Temperature
    		25 to 35°C (77 to 95°F)

    NOTICE:
    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.

    HINT:
    1. 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 (thermistor assembly) and the front evaporator temperature sensor (No. 1 cooler thermistor) to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.
    2. 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 is not output.



NG
Go to step 16
OK

REPLACE COOLER DRYER (Click here)  

16.REPLACE EXPANSION VALVE

  1. Replace the expansion valve with a normal one (Click here).

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


NEXT


17.CHARGE REFRIGERANT

  1. Add an appropriate amount of refrigerant (Click here).


NEXT


18.RECHECK DTC

  1. Recheck for the DTC when the following conditions are satisfied.
    Measurement Condition 
    Item
    		Condition
    Engine Speed
    		2000 rpm
    Vehicle Doors
    		Fully open
    Temperature Setting
    		Lo
    Blower Speed
    		Hi
    A/C Switch
    		On
    Air inlet control Switch
    		Recirculation
    Interior Temperature
    		25 to 35°C (77 to 95°F)

    NOTICE:
    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.

    HINT:
    1. 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 (thermistor assembly) and the front evaporator temperature sensor (No. 1 cooler thermistor) to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.
    2. 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 is not output.



NG
REPLACE CONDENSER (Click here)
OK

END