DTC    B1423/23    Pressure Sensor Circuit

for Preparation Click here

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

1. Disconnect the A/C pressure sensor connector.
   

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

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   A31-3 (+) - Body ground	Power switch on (IG)	4.75 to 5.25 V

   Text in Illustration 

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

NG	Go to step 5

OK

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A31-1 (-) - Body ground	Always	Below 1 Ω

   Text in Illustration 

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

NG	Go to step 6

OK

1. Reconnect the A/C pressure sensor connector.
   

2. Remove the A/C amplifier with the connectors still connected.
   

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

   Standard Voltage:

   Tester Connection	Condition	Specified Condition
   L17-9 (PRE) - Body ground	Power switch on (IG) (A/C: off)	0.73 to 4.84 V

   HINT:

   If the voltage is not as specified, 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 

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

NG	Go to step 7

OK

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)

   NOTICE:

   1. If refrigerant pressure on the high pressure line 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 function operates.
      
   2. It is necessary to measure the voltage over a period 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 signals from 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.

   
   
   

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

      Standard Voltage:

      Tester Connection	Condition	Specified Condition
      L17-9 (PRE) - Body ground	Power switch on (IG) (A/C: on)	0.73 to 4.84 V

      Result:

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

      Text in Illustration 

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

B	PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)
C	Go to step 13

A
REPLACE A/C AMPLIFIER (Click here)

1. Disconnect the A/C amplifier connector.
   

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A31-3 (+) - L17-10 (S5-3)	Always	Below 1 Ω
   L17-10 (S5-3) - Body ground	Always	10 kΩ or higher

   Text in Illustration 

   *1	Front view of wire harness connector (to A/C Amplifier)
   *2	Front view of wire harness connector (to A/C Pressure Sensor)

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE A/C AMPLIFIER (Click here)

1. Disconnect the A/C amplifier connector.
   

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A31-1 (-) - L17-13 (SG-2)	Always	Below 1 Ω
   L17-13 (SG-2) - Body ground	Always	10 kΩ or higher

   Text in Illustration 

   *1	Front view of wire harness connector (to A/C Amplifier)
   *2	Front view of wire harness connector (to A/C Pressure Sensor)

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE A/C AMPLIFIER (Click here)

1. Disconnect the A/C amplifier connector.
   

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A31-2 (PR) - L17-9 (PRE)	Always	Below 1 Ω
   L17-9 (PRE) - Body ground	Always	10 kΩ or higher

   Text in Illustration 

   *1	Front view of wire harness connector (to A/C Amplifier)
   *2	Front view of wire harness connector (to A/C Pressure Sensor)

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

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	Go to step 12

OK

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

NEXT

1. Recheck for the DTC 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)

   NOTICE:

   If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while.

   HINT:

   When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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 B1423/23 is output	A
   DTC B1423/23 is not output	B

   NOTICE:

   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 any refrigerant leaks as necessary.

B	END

A

1. Install the manifold gauge set.
   

2. Reconnect the A/C pressure sensor connector.
   

3. Turn the power switch on (IG).
   

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

   Standard Voltage:

   Tester Connection	Condition	Specified Condition
   L17-9 (PRE) - L17-13 (SG-2)	Refrigerant pressure: Normal pressure (less than 3.187 MPa [462 psi] and more than 0.39 MPa [57 psi])	1.0 to 4.912 V

   Text in Illustration 

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

NG	Go to step 19

OK
REPLACE A/C AMPLIFIER (Click here)

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

2. Repair the identified area of the A/C system.
   

3. Evacuate the A/C system.
   

NEXT
CHARGE REFRIGERANT (Click here)

1. Check that the cooling fan(s) operates normally.
   

   HINT:

   Refer to Cooling Fan Circuit (Click here).

NG	REPAIR COOLING FAN SYSTEM

OK

1. Use a refrigerant recovery unit to recover refrigerant.
   

2. Evacuate the A/C system.
   

3. 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, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for DTCs.

NEXT

1. Recheck for the DTC 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)

   NOTICE:

   If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because DTC may be set after the A/C has been operating for a while.

   HINT:

   1. When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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.
      
   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, 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, it indicates that the cooler dryer in the condenser is not able to absorb moisture in the refrigerant. In this case, to complete the repair, it is necessary to replace the cooler dryer.
      

   Result:

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

B	REPLACE COOLER DRYER (Click here)

A

1. Replace the expansion valve with a new or a known good one (Click here).
   

   HINT:

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

NEXT

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

NEXT

1. Recheck for the DTC 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)

   NOTICE:

   If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while.

   HINT:

   1. When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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.
      
   2. If refrigerant pressure is not normal after replacing the expansion valve with a new or a known good one, the condenser or pipes may be clogged with dirt, dust or other contaminants. In this case, clean or replace the condenser or pipes.
      

   Result:

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

B	REPLACE CONDENSER (Click here)

A
END

1. Replace the A/C pressure sensor (Click here).
   

   HINT:

   Since the A/C pressure sensor cannot be inspected while it is removed from the vehicle, replace the A/C pressure sensor with a new or a known good one and check that the condition returns to normal.

NEXT

1. Recheck for the DTC 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)

   NOTICE:

   If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while.

   HINT:

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

   Result:

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

B	REPLACE A/C AMPLIFIER (Click here)

A
END