B1423

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1423: Pressure Sensor Circuit

DTC B1423 - Pressure Sensor Circuit

DESCRIPTION

This DTC is output when refrigerant pressure on the high pressure side is extremely low (0.19 MPa (2.0 kgf/cm2, 28 psi) or less) or extremely high (3.14 MPa (32.0 kgf/cm2, 455 psi) or more). The pressure sensor, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs a refrigerant pressure signal to the air conditioning amplifier. The air conditioning amplifier converts this signal to pressure according to the sensor characteristics to control the compressor.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. CHECK REFRIGERANT PRESSURE

(a) Install the manifold gauge set Refrigerant.
(b) Read the manifold gauge pressure when the following conditions are established.
(1) Prepare the vehicle in accordance with the chart below.

(2) When the refrigerant volume is correct, the gauge reading indicates as follows:
Low pressure side:
0.15 to 0.25 MPa (1.5 to 2.5 kgf/cm2, 22 to 36 psi)
High pressure side:
1.37 to 1.57 MPa (14 to 16 kgf/cm2, 199 to 228 psi)
HINT: Pressure varies in accordance with certain conditions (outside air temperature, sunlight and wind).

NG -- CHECK FOR A/C SYSTEM LEAK
OK -- Continue to next step.
2. READ VALUE USING TECHSTREAM (REGULATOR PRESSURE SENSOR)
(a) Warm up the engine.
(b) Turn the ignition switch to OFF.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON.
(e) Turn the tester on.
(f) Select the following menus: Body Electrical / Air Conditioner / Data List /
(g) According to the display on tester, read the "Data List".
Regulator Pressure Sensor:

OK:
The display is as specified in the normal condition column.
Result:

C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
3. INSPECT LIQUID TUBE SUB-ASSEMBLY (A/C PRESSURE SENSOR)

(a) Install the manifold gauge set Refrigerant.
(b) Disconnect the A1 A/C pressure sensor connector.
(c) Connect the three 1.5 V dry cell batteries' positive (+) lead to terminal 3, and the negative (-) lead to terminal 1.
(d) Connect the voltmeter's positive (+) lead to terminal 2, and the negative (-) lead to terminal 1.
(e) Measure the voltage according to the value(s) in the table below.
Standard voltage:

(f) Reconnect the A/C pressure sensor connector.
NG -- REPLACE LIQUID TUBE SUB-ASSEMBLY
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (A/C PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER)

(a) Disconnect the A1 A/C pressure sensor connector.
(b) Disconnect the G7 air conditioning amplifier connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:

(d) Reconnect the air conditioning amplifier connector.
(e) Reconnect the A/C pressure sensor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE AIR CONDITIONING AMPLIFIER
5. CHECK FOR A/C SYSTEM LEAK
(a) Install the manifold gauge set Refrigerant.
(b) Recover the refrigerant from the A/C system using a refrigerant recovery unit.
(c) Evacuate the A/C system and check that vacuum can be maintained in it.
OK:
Vacuum can be maintained in the A/C system.
HINT: If vacuum cannot be maintained in the A/C system, refrigerant may be leaking from it. In this case, it is necessary to repair or replace the leaking part of the A/C system.

NG -- REPAIR A/C SYSTEM LEAK
OK -- Continue to next step.
6. CHARGE REFRIGERANT
(a) Add an appropriate amount of refrigerant Service and Repair.
NEXT -- Continue to next step.
7. RECHECK DTC
(a) Recheck for the DTC when the following conditions are satisfied.

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 the area where refrigerant leaks from as necessary.

B -- END
A -- REPLACE AIR CONDITIONING AMPLIFIER
8. REPAIR A/C SYSTEM LEAK
(a) Identify the area where refrigerant leaks from Service and Repair.
(b) Repair the identified area of the A/C system.
(c) Evacuate the A/C system.
NEXT -- Continue to next step.
9. CHARGE REFRIGERANT
(a) Use a refrigerant recovery unit to recover refrigerant.
(b) Evacuate the A/C system.
(c) Add an appropriate amount of refrigerant Service and Repair.
HINT: If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system may freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant, properly evacuate the system, add an appropriate amount of refrigerant, and check for the DTC.

NEXT -- Continue to next step.
10. RECHECK DTC
(a) Recheck for the DTC when the following conditions are satisfied.

NOTICE: 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 may freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant, 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, to complete the repair it is necessary to replace the cooler dryer.

Result:

B -- END
A -- REPLACE AIR CONDITIONING AMPLIFIER