DTC B1423/23: Pressure Sensor Circuit: Procedure

1. Disconnect the connector from the A/C pressure sensor.
   Fig 1: Identifying A16 Connector + Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A16-3 (+) - Body ground	Ignition switch ON	4.75 to 5.25 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to A/C Pressure Sensor)

NG → See step   11 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 2: Identifying A16 Connector - Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A16-1 (-) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to A/C Pressure Sensor)

NG → See step   12 

OK: Go to next step 

1. Reconnect the connector to the A/C pressure sensor.
2. Remove the A/C amplifier with the connectors still connected.
   Fig 3: Identifying E30 Connector PRE Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   E30-9 (PRE) - Body ground	Ignition switch ON (A/C: OFF)	0.7 to 4.8 V

   HINT: 

   If the measured voltage is not within the normal range, there may be a malfunction in the A/C amplifier, A/C pressure sensor, or wire harness. It is also possible that the amount of refrigerant may not be appropriate.

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (A/C Amplifier)

NG → See step   13 

OK: Go to next step 

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

   Item	Condition
   Vehicle Doors	Fully open
   Temperature Setting	MAX COLD
   Blower Speed	HI
   A/C Switch	ON
   R/F Switch	RECIRCULATION
   Interior Temperature	25 to 35°C (77 to 95°F)
   Engine Speed	2000 RPM

   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 function operates.
   • 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 the 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.

   1. Measure the voltage according to the value(s) in the table below.
      Fig 4: Identifying E30 Connector PRE Terminal

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection	Condition	Specified Condition
      E30-9 (PRE) - Body ground	Ignition switch ON (A/C: ON)	0.7 to 4.8 V

      Result

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

      TEXT IN ILLUSTRATION
      
      

      *a	Component with harness connected (A/C Amplifier)

C → See step   21 

B → See step   19 

A: Go to next step 

1. Check that the cooling fan operates normally.

   HINT: 

   • Refer to Cooling Fan Circuit for 2AZ-FE.
   • Refer to Cooling Fan Circuit for 2ZR-FE.

NG → REPAIR COOLING FAN SYSTEM 

OK: Go to next step 

1. Use a refrigerant recovery unit to recover refrigerant.
2. Evacuate the A/C system.
3. Add an appropriate amount of refrigerant. Refer to REPLACEMENT - Step 2 .

   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 DTCs.

NEXT: Go to next step 

1. Recheck for DTCs when the following conditions are satisfied.

   Item	Condition
   Vehicle Doors	Fully open
   Temperature Setting	MAX COLD
   Blower Speed	HI
   A/C Switch	ON
   R/F Switch	RECIRCULATION
   Interior Temperature	25 to 35°C (77 to 95°F)
   Engine Speed	2000 RPM

   NOTE:

   If refrigerant pressure on the high pressure side becomes high, the DTC will be set. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the A/C 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 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. In this case, to complete the repair, it is necessary to replace the cooler dryer.

   Result

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

B → See step   8 

A → See step   23 

1. Replace the expansion valve with a new one. Refer to DISASSEMBLY .

   HINT: 

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

NEXT: Go to next step 

1. Add an appropriate amount of refrigerant. Refer to REPLACEMENT - Step 2 .

NEXT: Go to next step 

1. Recheck for DTCs when the following conditions are satisfied.

   Item	Condition
   Vehicle Doors	Fully open
   Temperature Setting	MAX COLD
   Blower Speed	HI
   A/C Switch	ON
   R/F Switch	RECIRCULATION
   Interior Temperature	25 to 35°C (77 to 95°F)
   Engine Speed	2000 RPM

   NOTE:

   If refrigerant pressure on the high pressure side becomes high, the DTC will be set. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the A/C operates for a while.

   HINT: 

   • When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to the 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 new 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.

   Result

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

B → See step   24 

A → END 

1. Disconnect the connector from the A/C amplifier.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A16-3 (+) - E30-10 (S5-3)	Always	Below 1 Ω
   E30-10 (S5-3) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   21 

1. Disconnect the connector from the A/C amplifier.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A16-1 (-) - E30-13 (SG-2)	Always	Below 1 Ω
   E30-13 (SG-2) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   21 

1. Disconnect the connector from the A/C amplifier.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A16-2 (PR) - E30-9 (PRE)	Always	Below 1 Ω
   E30-9 (PRE) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Install the manifold gauge set.
2. Recover the refrigerant from the A/C system using a refrigerant recovery unit.
3. Evacuate the A/C system and check that vacuum can be maintained.

   OK

   Vacuum can be maintained in the A/C system.

   HINT: 

   If vacuum cannot be maintained in the A/C system, there may be a refrigerant leak. In this case, it is necessary to repair or replace the leaking part of the A/C system.

NG → See step   18 

OK: Go to next step 

1. Add an appropriate amount of refrigerant. Refer to REPLACEMENT - Step 2 .

NEXT: Go to next step 

1. Recheck for DTCs when the following conditions are satisfied.

   Item	Condition
   Vehicle Doors	Fully open
   Temperature Setting	MAX COLD
   Blower Speed	HI
   A/C Switch	ON
   R/F Switch	RECIRCULATION
   Interior Temperature	25 to 35°C (77 to 95°F)
   Engine Speed	2000 RPM

   NOTE:

   If refrigerant pressure on the high pressure side becomes high, the DTC will be set. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the A/C operates for a while.

   HINT: 

   When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to the 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.

   Result

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

   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.

B → See step   17 

A → END 

1. Install the manifold gauge set.
2. Disconnect the connector from the A/C pressure sensor.
3. Connect the three 1.5 V dry cell batteries' positive (+) lead to terminal 3, and the negative (-) lead to terminal 1.
   Fig 5: Inspecting A16 Connector Terminals & Graph

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Connect the voltmeter's positive (+) lead to terminal 2, and the negative (-) lead to terminal 1.
5. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A16-2 (PR) - A16-1 (-)	Refrigerant pressure: 0.39 to 3.187 MPa (57 to 463 psi)	1.0 to 4.8 V

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (A/C Pressure Sensor)
   *b	Voltage (V)
   *c	Refrigerant Pressure (MPa (psi))

NG → See step   20 

OK → See step   21 

1. Identify the area where refrigerant leaks from. Refer to REPLACEMENT - Step 4 .
2. Repair the identified area of the A/C system.
3. Evacuate the A/C system.

NEXT → See step   22