- An open or short in the air conditioner pressure sensor circuit.
- Refrigerant pressure on the high pressure side is extremely low or extremely high.
| Last Modified: 11-27-2007 | 1.6 C | |
| Service Category: Vehicle Interior | Section: Heating/Air Conditioning | |
| Model Year: 2008 | Model: LX570 | Doc ID: RM000003E0P002X |
| Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DESCRIPTION (2008 LX570) | ||
|
DTC |
B1423/23 |
Pressure Sensor Circuit |
DESCRIPTION
This DTC is stored when refrigerant pressure is extremely low (0.1762 MPa (1.8 kgf/cm2, 25 psi) or less) or extremely high (3.0732 MPa (31.4 kgf/cm2, 445 psi) or more). The air conditioner pressure sensor, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs the refrigerant pressure signal to the air conditioning amplifier assembly. The air conditioning amplifier assembly converts the signal to pressure according to the sensor characteristics to control the compressor.
HINT:
Be sure to check the refrigerant volume first when this DTC is output because this DTC can also be stored if there is no refrigerant in the cycle.
|
DTC Code |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
B1423/23 |
|
|
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
|
1. |
CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) |
(a) Disconnect the A13 air conditioner pressure sensor connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
A13-3 (+) - Body ground |
Engine switch on (IG) |
4.75 to 5.25 V |
|
|
2. |
CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) |
(a) 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 |
|
|
3. |
INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) |
(a) Reconnect the A13 air conditioner pressure sensor connector.
(b) Remove the air conditioning amplifier assembly with its connectors still connected.
|
(c) Measure the voltage according to the value(s) in the table below. Standard Voltage:
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. |
|
|
4. |
INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) |
(a) Measure the voltage when the following conditions are satisfied.
Measurement Condition
|
Item |
Condition |
|---|---|
|
Engine Speed |
1500 rpm |
|
Vehicle Doors |
Fully open |
|
Temperature Setting |
Lo |
|
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 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 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. Standard Voltage:
|
|
|
5. |
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) |
(a) Disconnect the E35 air conditioning amplifier assembly connector.
(b) Disconnect the A13 air conditioner pressure sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A13-3 (+) - E35-27 (S5-1) |
Always |
Below 1 Ω |
|
E35-27 (S5-1) - Body ground |
Always |
10 kΩ or higher |
|
|
6. |
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) |
(a) Disconnect the E35 air conditioning amplifier assembly connector.
(b) Disconnect the A13 air conditioner pressure sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A13-1 (-) - E35-16 (SG-2) |
Always |
Below 1 Ω |
|
E35-16 (SG-2) - Body ground |
|
|
7. |
CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) |
(a) Disconnect the E35 air conditioning amplifier assembly connector.
(b) Disconnect the A13 air conditioner pressure sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A13-2 (PR) - E35-20 (PRE) |
Always |
Below 1 Ω |
|
E35-20 (PRE) - Body ground |
Always |
10 kΩ or higher |
|
|
8. |
INSPECT FOR AIR CONDITIONING SYSTEM LEAK |
(a) Install the manifold gauge set.
(b) Recover the refrigerant from the air conditioning system using a refrigerant recovery unit.
(c) 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.
|
|
9. |
CHARGE REFRIGERANT |
(a) Add an appropriate amount of refrigerant
.
|
|
10. |
RECHECK DTC |
(a) Recheck for the DTC when the following conditions are satisfied.
Measurement Condition
|
Item |
Condition |
|---|---|
|
Engine Speed |
1500 rpm |
|
Vehicle Doors |
Fully open |
|
Temperature Setting |
Lo |
|
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 side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) 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 the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.
OK:
DTC B1423 is not output.
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 refrigerant when the level was insufficient. Therefore, identify and repair the area where refrigerant leaks as necessary.
|
|
11. |
INSPECT AIR CONDITIONER PRESSURE SENSOR |
(a) Install the manifold gauge set.
(b) Reconnect the A13 air conditioner pressure sensor connector.
(c) Remove the air conditioning amplifier assembly with its connectors still connected.
(d) Turn the engine switch on (IG).
(e) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
E35-20 (PRE) - E35-16 (SG-2) |
Refrigerant pressure: Normal pressure (less than 3.0732 MPa [31.4 kgf/cm2, 445 psi] and more than 0.1762 MPa [1.8 kgf/cm2, 25 psi]) |
1.0 to 4.8 V |
|
Refrigerant pressure: Abnormal (less than 0.1762 MPa [1.8 kgf/cm2, 25 psi]) |
Below 1 V |
|
|
Refrigerant pressure: Abnormal (more than 3.0732 MPa [31.4 kgf/cm2, 445 psi]) |
4.8 V or higher |
|
|
12. |
REPAIR AIR CONDITIONING SYSTEM LEAK |
(a) Identify the area where refrigerant leaks
.
(b) Repair the identified area of the air conditioning system.
(c) Evacuate the air conditioning system.
|
|
13. |
INSPECT CONDENSER FAN |
(a) Inspect that the condenser fan operates normally
.
|
|
14. |
CHARGE REFRIGERANT |
(a) Use a refrigerant recovery unit to recover refrigerant.
(b) Evacuate the air conditioning system.
(c) 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 check for the DTC.
|
|
15. |
RECHECK DTC |
(a) Recheck for the DTC when the following conditions are satisfied.
Measurement Condition
|
Item |
Condition |
|---|---|
|
Engine Speed |
1500 rpm |
|
Vehicle Doors |
Fully open |
|
Temperature Setting |
Lo |
|
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 side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) 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 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 procedure, it indicates that the cooler dryer in the cooler condenser assembly 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.
OK:
DTC B1423 is not output.
|
|
16. |
REPLACE COOLER EXPANSION VALVE |
(a) Replace the cooler expansion valve with a normal one
.
HINT:
Replace the cooler expansion valve with a normal one because the cooler expansion valve is either stuck or clogged.
|
|
17. |
CHARGE REFRIGERANT |
(a) Add an appropriate amount of refrigerant
.
|
|
18. |
RECHECK DTC |
(a) Recheck for the DTC when the following conditions are satisfied.
Measurement Condition
|
Item |
Condition |
|---|---|
|
Engine Speed |
1500 rpm |
|
Vehicle Doors |
Fully open |
|
Temperature Setting |
Lo |
|
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 side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) 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 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 cooler condenser assembly or pipes may be clogged due to dirt, dust or other contaminants. In this case, clean or replace the cooler condenser assembly or pipes.
OK:
DTC B1423 is not output.
|
|
|