HEATING / AIR CONDITIONING AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System) B1423/23 Pressure Sensor Circuit

DESCRIPTION

This DTC is stored if refrigerant pressure on the high pressure side is extremely low (176 kPa (1.8 kgf/cm², 26 psi) or less) or extremely high (3025 kPa (30.8 kgf/cm², 439 psi) or more). The air conditioner pressure sensor, which is installed on the high pressure side pipe 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 No.	Detection Item	DTC Detection Condition	Trouble Area	Memory
B1423/23	Pressure Sensor Circuit	· Open or short in air conditioner pressure sensor circuit · Refrigerant pressure on high pressure side is extremely low (176 kPa (1.8 kgf/cm², 26 psi) or less) or extremely high (3025 kPa (30.8 kgf/cm², 439 psi) or more)	· Air conditioner pressure sensor · Harness or connector between air conditioner pressure sensor and air conditioning amplifier assembly · Air conditioning amplifier assembly · Cooler expansion valve (blocked, stuck) · Cooler condenser assembly (blocked, deterioration of cooling capacity due to dirt) · Cooler dryer (moisture in the refrigerant cycle cannot be absorbed) · Cooling fan system (cooler condenser assembly cannot be cooled down) · Air conditioning system (leaks, blocked)	-

WIRING DIAGRAM

2.229,1.969 2.323,2.146 0.094,0.177 10 false 1 2.229,1.021 2.323,1.198 0.094,0.177 10 false 2 4.854,1.021 4.948,1.198 0.094,0.177 10 false 9 4.771,1.969 4.948,2.146 0.177,0.177 10 false 13 1.885,1.115 2.229,1.417 0.344,0.302 10 false PR 1.021,3.906 3.104,4.24 2.083,0.333 10 false Air Conditioner Pressure Sensor 1.021,3.75 1.365,3.948 0.344,0.198 10 false A11 5.083,2.063 5.427,2.24 0.344,0.177 10 false SG-2 5.083,3.021 5.427,3.198 0.344,0.177 10 false S5-3 4.646,3.729 5.073,3.969 0.427,0.24 10 false E102 4.646,3.885 6.198,4.292 1.552,0.406 10 false Air Conditioning Amplifier Assembly 2.229,2.927 2.323,3.104 0.094,0.177 10 false 3 2,2.052 2.094,2.229 0.094,0.177 10 false - 2,3.021 2.104,3.198 0.104,0.177 10 false + 4.771,2.927 4.948,3.104 0.177,0.177 10 false 10 5.083,1.115 5.417,1.292 0.333,0.177 10 false PRE

CAUTION / NOTICE / HINT

HINT:: If DTC B1423/23 and B14B8 are output at the same time, troubleshoot for DTC B1423/23 first.

PROCEDURE

1.CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

Disconnect the A11 air conditioner pressure sensor connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A11-3 (+) - Body ground	Ignition switch ON	4.75 to 5.25 V

Result:

Proceed to
OK
NG

2.CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)

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

2.CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A11-1 (-) - Body ground	Always	Below 1 Ω

Result:

Proceed to
OK
NG

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

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

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

Reconnect the A11 air conditioner pressure sensor connector.

Remove the air conditioning amplifier assembly with the connectors still connected.

1.25,0.167 1.667,0.417 0.417,0.25 0.875,1.656 1.5,1.031 false 0.208,0.177 0.531,0.479 0.323,0.302 10 false *a 0.635,1.667 1.115,1.927 0.479,0.26 10 false PRE 1.292,0.219 1.75,0.542 0.458,0.323 10 false E102

*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
E102-9 (PRE) - Body ground	Ignition switch ON (A/C switch: Off)	0.62 to 4.73 V

HINT:: If the voltage is not as specified, 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.

Result:

Proceed to
OK
NG

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

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

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

Measure the voltage when the following conditions are met.

Measurement Condition:
Item	Condition
Vehicle doors	Fully open
Temperature setting	MAX COLD
Blower speed	HI
A/C switch	On
Recirculation/fresh switch	RECIRCULATION
Interior temperature	25 to 35°C (77 to 95°F)
Engine speed	2000 rpm

NOTICE:: ·

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 malfunction 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 thermistor assembly and the No. 1 cooler thermistor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

*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
E102-9 (PRE) - Body ground	Ignition switch ON (A/C switch: On)	0.62 to 4.73 V

Result:

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

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

Click hereVehicle Interior>HEATING / AIR CONDITIONING>AIR CONDITIONING AMPLIFIER>REMOVAL

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

Click hereVehicle Interior>HEATING / AIR CONDITIONING>AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System)>PROBLEM SYMPTOMS TABLE

5.INSPECT COOLING FAN SYSTEM

Check if the cooling fan operates normally.

Click hereEngine / Hybrid System>2ZR-FE COOLING>COOLING FAN SYSTEM>ON-VEHICLE INSPECTION

Result:

Proceed to
OK
NG

6.CHARGE SYSTEM WITH REFRIGERANT

GO TO COOLING FAN SYSTEM

Click hereEngine / Hybrid System>2ZR-FE COOLING>COOLING FAN SYSTEM>ON-VEHICLE INSPECTION

6.CHARGE SYSTEM WITH REFRIGERANT

Use a refrigerant recovery unit to recover refrigerant.

Evacuate the air conditioning system.

Add an appropriate amount of refrigerant.

Click hereVehicle Interior>HEATING / AIR CONDITIONING>REFRIGERANT>REPLACEMENT

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 cooler 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.

Result:

Proceed to
NEXT

7.RECHECK FOR DTC

Recheck for DTCs when the following conditions are met.

Measurement Condition:
Item	Condition
Vehicle doors	Fully open
Temperature setting	MAX COLD
Blower speed	HI
A/C switch	On
Recirculation/fresh switch	RECIRCULATION
Interior temperature	25 to 35°C (77 to 95°F)
Engine speed	2000 rpm

Body Electrical > Air Conditioner > Trouble Codes: 50001 121

NOTICE:: If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. It is necessary to operate the air conditioning system for a certain amount of time (approximately 10 minutes) because the DTC may be stored after the air conditioning 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 thermistor assembly and the No. 1 cooler thermistor 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 cooler 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 work, it indicates that the cooler dryer in the cooler condenser assembly is not able to absorb moisture in the refrigerant cycle. It is necessary to replace the cooler dryer in order to complete the repair.

Result:

Result	Proceed to
DTC B1423/23 is output	A
DTC B1423/23 is not output	B

8.REPLACE COOLER EXPANSION VALVE

REPLACE CONDENSER ASSEMBLY WITH RECEIVER

Click hereVehicle Interior>HEATING / AIR CONDITIONING>CONDENSER>REMOVAL

8.REPLACE COOLER EXPANSION VALVE

Replace the cooler expansion valve with a new or known good one.

Click hereVehicle Interior>HEATING / AIR CONDITIONING>COOLER EXPANSION VALVE>REMOVAL

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

Result:

Proceed to
NEXT

9.CHARGE SYSTEM WITH REFRIGERANT

Use a refrigerant recovery unit to recover refrigerant.

Evacuate the air conditioning system.

Add an appropriate amount of refrigerant.

Click hereVehicle Interior>HEATING / AIR CONDITIONING>REFRIGERANT>REPLACEMENT

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 cooler 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.

Result:

Proceed to
NEXT

10.RECHECK FOR DTC

Recheck for DTCs when the following conditions are met.

Measurement Condition:
Item	Condition
Vehicle doors	Fully open
Temperature setting	MAX COLD
Blower speed	HI
A/C switch	On
Recirculation/fresh switch	RECIRCULATION
Interior temperature	25 to 35°C (77 to 95°F)
Engine speed	2000 rpm

Body Electrical > Air Conditioner > Trouble Codes: 50001 121

NOTICE:: If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. It is necessary to operate the air conditioning system for a certain amount of time (approximately 10 minutes) because the DTC may be stored after the air conditioning 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 thermistor assembly and the No. 1 cooler thermistor 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 cooler expansion valve with a new or known good one, the cooler condenser assembly or pipes may be clogged due to dirt, dust or other foreign matter. In this case, clean or replace the cooler condenser assembly or pipes.

Result:

Result	Proceed to
DTC B1423/23 is not output	A
DTC B1423/23 is output	B

END

CLEAN OR REPLACE CONDENSER ASSEMBLY WITH RECEIVER

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

Disconnect the A11 air conditioner pressure sensor connector.

Disconnect the E102 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A11-2 (PR) - E102-9 (PRE)	Always	Below 1 Ω
E102-9 (PRE) or A11-2 (PR) - Body ground	Always	10 kΩ or higher

Result:

Proceed to
OK
NG

12.INSPECT FOR AIR CONDITIONING SYSTEM LEAK

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.INSPECT FOR AIR CONDITIONING SYSTEM LEAK

Install a 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.

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.

Result:

Proceed to
OK
NG

13.CHARGE SYSTEM WITH REFRIGERANT

16.REPAIR AIR CONDITIONING SYSTEM LEAK

13.CHARGE SYSTEM WITH REFRIGERANT

Use a refrigerant recovery unit to recover refrigerant.

Evacuate the air conditioning system.

Add an appropriate amount of refrigerant.

Click hereVehicle Interior>HEATING / AIR CONDITIONING>REFRIGERANT>REPLACEMENT

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 cooler 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.

Result:

Proceed to
NEXT

14.RECHECK FOR DTC

Recheck for the DTC when the following conditions are met.

Measurement Condition:
Item	Condition
Vehicle doors	Fully open
Temperature setting	MAX COLD
Blower speed	HI
A/C switch	On
Recirculation/fresh switch	RECIRCULATION
Interior temperature	25 to 35°C (77 to 95°F)
Engine speed	2000 rpm

Body Electrical > Air Conditioner > Trouble Codes: 50001 121

NOTICE:: If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. It is necessary to operate the air conditioning system for a certain amount of time (approximately 10 minutes) because the DTC may be stored after the air conditioning 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 thermistor assembly and the No. 1 cooler thermistor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

Result:

Result	Proceed to
DTC B1423/23 is output	A
DTC B1423/23 is not output	B

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 too much refrigerant when the level was insufficient. Therefore, identify and repair the area where refrigerant leaks from as necessary.

15.INSPECT AIR CONDITIONER PRESSURE SENSOR

END

15.INSPECT AIR CONDITIONER PRESSURE SENSOR

Install a manifold gauge set.

Reconnect the A11 air conditioner pressure sensor connector.

Turn the ignition switch to ON.

*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
E102-9 (PRE) - E102-13 (SG-2)	Refrigerant pressure: (less than 3025 kPa (30.8 kgf/cm², 439 psi) and more than 176 kPa (1.8 kgf/cm², 26 psi))	0.62 to 4.73 V

Result:

Proceed to
OK
NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

Click hereVehicle Interior>HEATING / AIR CONDITIONING>AIR CONDITIONING AMPLIFIER>REMOVAL

REPLACE AIR CONDITIONER PRESSURE SENSOR

Click hereVehicle Interior>HEATING / AIR CONDITIONING>REFRIGERANT LINE>COMPONENTS

16.REPAIR AIR CONDITIONING SYSTEM LEAK

Identify the area where refrigerant leaks from.

Click hereVehicle Interior>HEATING / AIR CONDITIONING>REFRIGERANT>REPLACEMENT

Repair the identified area of the air conditioning system.

Evacuate the air conditioning system.

Result:

Proceed to
NEXT

CHARGE SYSTEM WITH REFRIGERANT

Click hereVehicle Interior>HEATING / AIR CONDITIONING>REFRIGERANT>REPLACEMENT

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

Disconnect the E102 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A11-1 (-) - E102-13 (SG-2)	Always	Below 1 Ω
E102-13 (SG-2) or A11-1 (-) - Body ground	Always	10 kΩ or higher

Result:

Proceed to
OK
NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

Click hereVehicle Interior>HEATING / AIR CONDITIONING>AIR CONDITIONING AMPLIFIER>REMOVAL

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

Disconnect the E102 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A11-3 (+) - E102-10 (S5-3)	Always	Below 1 Ω
E102-10 (S5-3) or A11-3 (+) - Body ground	Always	10 kΩ or higher

Result:

Proceed to
OK
NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

Click hereVehicle Interior>HEATING / AIR CONDITIONING>AIR CONDITIONING AMPLIFIER>REMOVAL

REPAIR OR REPLACE HARNESS OR CONNECTOR