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 (3.0732 MPa (31.4 kgf/cm2, 445 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 assembly. The air conditioning amplifier assembly converts the signal to pressure according to the sensor characteristics to control the compressor.
Tech Tips
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 |
---|---|---|
B1423/23 |
|
|
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)
Disconnect the A13 air conditioner pressure sensor connector.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||
---|---|---|---|---|---|---|
|
NG |
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Click here |
OK |
CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
NG |
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Click here |
OK |
INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)
Reconnect the A13 air conditioner pressure sensor connector.
Remove the air conditioning amplifier assembly with its connectors still connected.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||
---|---|---|---|---|---|---|
|
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 the amount of refrigerant may not be appropriate.
NG |
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Click here |
OK |
INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)
Measure the voltage when the following conditions are satisfied.
Item | Condition |
---|---|
Engine Speed | 1500 rpm |
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 and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||
---|---|---|---|---|---|---|
|
NG |
INSPECT CONDENSER FAN Click here |
OK |
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)
Disconnect the E35 air conditioning amplifier assembly connector.
Disconnect the A13 air conditioner pressure sensor connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)
Disconnect the E35 air conditioning amplifier assembly connector.
Disconnect the A13 air conditioner pressure sensor connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)
Disconnect the E35 air conditioning amplifier assembly connector.
Disconnect the A13 air conditioner pressure sensor connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
INSPECT FOR AIR CONDITIONING SYSTEM LEAK
Install the manifold gauge set.
Recover the refrigerant from the air conditioning system using a refrigerant recovery unit.
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 |
CHARGE REFRIGERANT
Add an appropriate amount of refrigerant Click here.
NEXT |
RECHECK DTC
Recheck for the DTC when the following conditions are satisfied.
Item | Condition |
---|---|
Engine Speed | 1500 rpm |
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 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.
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 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 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 |
CHECK AIR CONDITIONER PRESSURE SENSOR Click here |
OK |
END
CHECK AIR CONDITIONER PRESSURE SENSOR
Install the manifold gauge set.
Reconnect the A13 air conditioner pressure sensor connector.
Remove the air conditioning amplifier assembly with its connectors still connected Click here.
Turn the engine switch on (IG).
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
NG |
REPLACE AIR CONDITIONER PRESSURE SENSOR Click here |
OK |
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here
REPAIR AIR CONDITIONING SYSTEM LEAK
Identify the area where refrigerant leaks Click here.
Repair the identified area of the air conditioning system.
Evacuate the air conditioning system.
NEXT |
CHARGE REFRIGERANT Click here
INSPECT CONDENSER FAN
Inspect that the condenser fan operates normally Click here.
NG |
REPLACE CONDENSER FAN Click here |
OK |
CHARGE REFRIGERANT
Use a refrigerant recovery unit to recover refrigerant.
Evacuate the air conditioning system.
Add an appropriate amount of refrigerant Click here.
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 the DTC.
NEXT |
RECHECK DTC
Recheck for the DTC when the following conditions are satisfied.
Item | Condition |
---|---|
Engine Speed | 1500 rpm |
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 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.
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 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. |
NG |
REPLACE COOLER EXPANSION VALVE Click here |
OK |
REPLACE COOLER DRYER Click here
REPLACE COOLER EXPANSION VALVE
Replace the cooler expansion valve with a normal one.
Tech Tips
for LHD: Click here.
for RHD: Click here.
Replace the cooler expansion valve with a normal one because the cooler expansion valve is either stuck or clogged.
NEXT |
CHARGE REFRIGERANT
Add an appropriate amount of refrigerant Click here.
NEXT |
RECHECK DTC
Recheck for the DTC when the following conditions are satisfied.
Item | Condition |
---|---|
Engine Speed | 1500 rpm |
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 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.
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 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. |
NG |
REPLACE COOLER CONDENSER ASSEMBLY Click here |
OK |
END