DTC B1423 Pressure Sensor Circuit

Disconnect the A13 air conditioner pressure sensor connector.

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

• Standard Voltage:

• Tester Connection	Switch Condition	Specified Condition
  A13-3 (+) - Body ground	Ignition switch ON	4.75 to 5.25 V

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

• Standard Resistance:

• Tester Connection	Condition	Specified Condition
  A13-1 (-) - Body ground	Always	Below 1 Ω

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:

• Tester Connection	Switch Condition	Specified Condition
  E81-9 (PRE) - E81-13 (SG-2)	Engine idling Blower switch LO level A/C switch off	0.63 to 4.72 V

• HINT:

• 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.

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

• Standard Resistance:

• Tester Connection	Switch Condition	Specified Condition
  E81-13 (SG-2) - Body ground	Always	Below 1 Ω

Remove the air conditioning amplifier assembly with its connectors still connected ().

Measure the voltage when the following conditions are met.

• NOTICE:

• 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 and evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

Disconnect the A13 air conditioner pressure sensor connector.

Disconnect the E81 air conditioning amplifier assembly connector.

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

• Standard Resistance:

• Tester Connection	Condition	Specified Condition
  A13-1 (-) - E81-13 (SG-2)	Always	Below 1 Ω
  A13-3 (+) - E81-30 (S5-1)	Always	Below 1 Ω
  E81-13 (SG-2) - Body ground	Always	10 kΩ or higher
  E81-30 (S5-1) - Body ground	Always	10 kΩ or higher

Disconnect the A13 air conditioner pressure sensor connector.

Disconnect the E81 air conditioning amplifier assembly connector.

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

• Standard Resistance:

• Tester Connection	Condition	Specified Condition
  A13-2 (PR) - E81-9 (PRE)	Always	Below 1 Ω
  E81-9 (PRE) - Body ground	Always	10 kΩ or higher

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 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.

Use a refrigerant recovery unit to recover refrigerant.

Evacuate the air conditioning system.

Add an appropriate amount of refrigerant ().

• 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 then check for the DTC.

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

• NOTICE:

• 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.

• 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 and evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

• 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 leakage. Therefore, identify and repair the area where refrigerant leaks as necessary. The root cause of excessive refrigerant may be adding too much refrigerant.

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:

• Tester Connection	Switch Condition	Specified Condition
  E81-9 (PRE) - E81-13 (SG-2)	Engine idling Blower switch LO level A/C switch on	0.63 to 4.72 V

Temporarily replace the air conditioner pressure sensor with a new or normally functioning one ().

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

• NOTICE:

• 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.

• HINT:

Identify the area where refrigerant leaks ().

Repair the identified area of the air conditioning system.

Evacuate the air conditioning system.

Use a refrigerant recovery unit to recover refrigerant.

Evacuate the air conditioning system.

Add an appropriate amount of refrigerant ().

• 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 then check for the DTC.

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

• NOTICE:

• 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.

• HINT:

Temporarily replace the cooler expansion valve with a new or normally functioning one.

• HINT:

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

Use a refrigerant recovery unit to recover refrigerant.

Evacuate the air conditioning system.

Add an appropriate amount of refrigerant ().

• 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 then check for the DTC.

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

• NOTICE:

• 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.

• HINT: