DTC B1423/23: Pressure Sensor Circuit: Procedure
- CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)
- Disconnect the connector from the A/C pressure sensor.
- 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 (IG) Approx. 5 V
NG → See step 5
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)
- Measure the resistance according to the value(s) in the table below.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard resistance
Tester Connection Condition Specified Condition A11-1 (-) - Body ground Always Below 1 Ω
NG → See step 6
OK: Go to next step
- Measure the resistance according to the value(s) in the table below.
- INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)
- Reconnect the connector to the A/C pressure sensor.
- Remove the Air Conditioning amplifier with connectors still connected.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
Tester Connection Condition Specified Condition D37-9 (PRE) - Body ground Ignition switch on (IG)
(A/C: OFF)0.5 to 4.8 V HINT:
If the measured voltage is not within the normal range, there may be a malfunction in the Air Conditioning amplifier, A/C pressure sensor, or wire harness. It is also possible that the amount of refrigerant may not be appropriate.
NG → See step 7
OK: Go to next step
- INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)
- 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 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.
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.
- Measure the voltage according to the value(s) in the table below.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard voltage
Tester Connection Condition Specified Condition D37-9 (PRE) - Body ground Ignition switch on (IG)
(A/C: ON)0.5 to 4.83 V Result
Result Proceed to OK (When troubleshooting according to DTC) A OK (When troubleshooting according to PROBLEM SYMPTOMS TABLE) B NG C
B → See step 19
C → See step 13
A → REPAIR OR REPLACE HARNESS OR CONNECTOR
- Measure the voltage when the following conditions are satisfied.
- CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - A/C PRESSURE SENSOR)
- Disconnect the connector from the Air Conditioning amplifier.
- Measure the resistance according to the value(s) in the table below.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard resistance
Tester Connection Condition Specified Condition A11-3 (+) - D37-10 (S5-3) Always Below 1 Ω D37-10 (S5-3) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 21
- CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - A/C PRESSURE SENSOR)
- Disconnect the connector from the Air Conditioning amplifier.
- Measure the resistance according to the value(s) in the table below.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard resistance
Tester Connection Condition Specified Condition A11-1 (-) - D37-13 (SG-2) Always Below 1 Ω D37-13 (SG-2) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 21
- CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - A/C PRESSURE SENSOR)
- Disconnect the connector from the Air Conditioning amplifier.
- Measure the resistance according to the value(s) in the table below.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard resistance
Tester Connection Condition Specified Condition A11-2 (PR) - D37-9 (PRE) Always Below 1 Ω D37-9 (PRE) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- INSPECT FOR A/C 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.
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.
NG → See step 12
OK: Go to next step
- CHARGE REFRIGERANT
- Add an appropriate amount of refrigerant. Refer to REPLACEMENT - Step 2 .
NEXT: Go to next step
- RECHECK DTC
- 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) Engine Speed 2000 RPM NOTE:If refrigerant pressure on the high pressure side becomes high, the DTC will be set. 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.
Result
Result Proceed to DTC B1423 is output A DTC B1423 is not 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 → END
A: Go to next step
- Recheck for the DTC when the following conditions are satisfied.
- INSPECT A/C PRESSURE SENSOR
- Install the manifold gauge set.
- Disconnect the connector from the A/C pressure sensor.
- Connect the three 1.5 V dry cell batteries' positive (+) lead to terminal 3, and the negative (-) lead to terminal 1.
- Connect the voltmeter's positive (+) lead to terminal 2, and the negative (-) lead to terminal 1.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
Tester Connection Condition Specified Condition 2 - 1 Refrigerant pressure:
0.39 to 3.187 MPa (57 to 463 psi)1.0 to 4.8 V
NG → See step 20
OK → See step 21
- REPAIR A/C SYSTEM LEAK
- Identify the area where refrigerant leaks from. Refer to REPLACEMENT - Step 4 .
- Repair the identified area of the Air Conditioning system.
- Evacuate the A/C system.
NEXT → CHARGE REFRIGERANT
- INSPECT COOLING FAN SYSTEM
- Check if that the cooling fan operates normally.
HINT:
- Cooling Fan Circuit. Refer to Cooling Fan Circuit .
NG → REPAIR COOLING FAN SYSTEM
OK: Go to next step
- Check if that the cooling fan operates normally.
- CHARGE REFRIGERANT
- Use a refrigerant recovery unit to recover refrigerant.
- Evacuate the Air Conditioning system.
- 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 the DTC.
NEXT: Go to next step
- RECHECK DTC
- 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) Engine Speed 2000 RPM NOTE:If refrigerant pressure on the high pressure side becomes high, the DTC will be set. It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set 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 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 work, it indicates that the cooler dryer in the condenser is not able to absorb moisture in the refrigerant cycle. In this case, in order to complete the repair it is necessary to replace the cooler dryer.
Result
Result Proceed to DTC B1423 is output A DTC B1423 is not output B
B → See step 22
A: Go to next step
- Recheck for the DTC when the following conditions are satisfied.
- REPLACE EXPANSION VALVE
- Replace the expansion valve with a normal one. Refer to DISASSEMBLY
.
HINT:
Replace the expansion valve with a normal one because the expansion valve is either stuck or clogged.
NEXT → See step 17
- Replace the expansion valve with a normal one. Refer to DISASSEMBLY
.
- CHARGE REFRIGERANT
- Add an appropriate amount of refrigerant. Refer to REPLACEMENT - Step 2 .
NEXT: Go to next step
- RECHECK DTC
- 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 RECIRCULATE 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 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 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 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 → REPLACE CONDENSER
A → END
- Recheck for the DTC when the following conditions are satisfied.
- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to PROBLEM SYMPTOMS TABLE
- REPLACE A/C PRESSURE SENSOR. Refer to COMPONENTS
- REPLACE AIR CONDITIONING AMPLIFIER. Refer to REMOVAL - Step 6
- CLEAN ON REPLACE CONDENSER OR PIPE. Refer to REMOVAL - Step 14