Lexus IS250 IS220d GSE20 ALE20 - AIR CONDITIONING
CHECK WIRE HARNESS (PRESSURE SENSOR - A/C AMPLIFIER)
DTC B1423/23 Pressure Switch Circuit
DESCRIPTION
This DTC is output when refrigerant pressure 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 A/C amplifier. The A/C amplifier converts this 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 output if there is no refrigerant in the system.
| DTC No. | DTC Detection Condition | Trouble Area |
| B1423/23 | Open or short in pressure switch circuit | Pressure sensor Harness and connector between pressure sensor and A/C amplifier Refrigerant pipe line A/C amplifier |
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.CHECK REFRIGERANT |
Check the sight glass of the cooler unit refrigerant liquid pipe.
Prepare the vehicle according to the chart below.
| Item | Condition |
| Vehicle Doors | Fully open |
| Temperature Setting | MAX COLD |
| Blower Speed | HI |
| A/C | ON |
Compare the sight glass to the following chart.
| Item | Symptom | Amount of Refrigerant | Corrective Actions |
| 1 | Bubbles visible | Insufficient* | Check for gas leakage and repair if necessary Add refrigerant until bubbles disappear |
| 2 | No bubbles visible | Empty, insufficient, or excessive | Refer to 3 and 4 |
| 3 | No temperature difference between compressor inlet and outlet | Empty or nearly empty | Check for gas leakage with gas leak detector and repair if necessary Evacuate A/C system and recharge with proper amount of refrigerant |
| 4 | Considerable temperature difference between compressor inlet and outlet | Proper or excessive | Refer to 5 and 6 |
| 5 | Immediately after air conditioning is turned OFF, refrigerant clears | Excessive | Recover refrigerant Evacuate A/C system and recharge with proper amount of refrigerant |
| 6 | Immediately after air conditioning is turned OFF, refrigerant foams and then becomes clear | Proper | - |
*: Bubbles in the sight glass with the vehicle interior temperature above 35°C (95°F) can be considered normal if cooling is sufficient.
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| OK | |
| 2.CHECK WIRE HARNESS (PRESSURE SENSOR - A/C AMPLIFIER) |
Disconnect the pressure sensor connector.
Disconnect the A/C amplifier connector.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
Tester Connection Condition Specified Condition B7-2 (PR) - J58-13 (PRE) Always Below 1 Ω B7-3 (+) - J58-26 (S5-2) Always Below 1 Ω B7-1 (-) - J58-38 (SG-2) Always Below 1 Ω J58-13 (PRE) - Body ground Always 10 kΩ or higher J58-26 (S5-2) - Body ground Always 10 kΩ or higher J58-38 (SG-2) - Body ground Always 10 kΩ or higher
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| OK | |
| 3.INSPECT PRESSURE SENSOR |
Install the manifold gauge set .
Connect the three 1.5 V dry cell batterie's positive (+) lead to terminal 3 and the negative (-) lead to terminal 1. Then connect the voltmeter's positive (+) lead to terminal 2 and the negative (-) lead to terminal 1. Measure the voltage.
- OK:
- The voltage changes according to refrigerant pressure, as shown in the graph.
- Result:
Result Proceed to NG A OK (When troubleshooting according to the DTC) B OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE) C
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| A | ||
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