On-Vehicle Inspection

WARNING: This page is about a different car, the 2004 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT REFRIGERANT VOLUME
Observe the sight glass on the liquid tube.

Test conditions:
- Running engine at 1,500 rpm
- Blower speed control switch at "HI" position
- A/C switch ON
- Temperature control dial at "COOL" position
- Fully open the doors
  
  Fig 1: Identifying Sight Glass On Liquid Tube
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Refrigerant Volume Inspection Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET
This is a method in which the trouble is located by using a manifold gauge set. Read the manifold gauge pressure when these conditions are established.

Test conditions:
- Temperature at the air inlet with the switch set at RECIRC is 30 - 35°C (86 - 95°F)
- Engine running at 2,000 rpm
- Blower speed control switch at "HI" position
- Temperature control dial on "COOL" position
HINT:

It should be noted that the gauge indications may vary slightly due to ambient temperature conditions.

Fig 3: Inspecting Refrigerant Pressure With Manifold Gauge Set (Normally Functioning Refrigeration System)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Normally functioning refrigeration system.
  Gauge reading:
  1. Low pressure side: 0.15 - 0.25 MPa (1.5 - 2.5 kgf/cm ²)
  2. High pressure side: 1.37 - 1.57 MPa (14 - 15 kgf/cm ²)
2. Moisture present in refrigeration system.
  
  Fig 4: Inspecting Refrigerant Pressure With Manifold Gauge Set For Symptom A/C System Periodically Cools & Then Fails To Cool
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 5: Symptom Table - A/C System Periodically Cools & Then Fails To Cool
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Insufficient cooling
  
  Fig 6: Inspecting Refrigerant Pressure With Manifold Gauge Set For Insufficient Cooling
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 7: Symptom Table - Insufficient Cooling
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Poor circulation of refrigerant
  
  Fig 8: Inspecting Refrigerant Pressure With Manifold Gauge Set For Poor Circulation Of Refrigerant
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 9: Symptom Table - Poor Circulation Of Refrigerant
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Refrigerant does not circulate
  
  Fig 10: Inspecting Refrigerant Pressure With Manifold Gauge Set - Refrigerant Does Not Circulate
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 11: Symptom Table - Refrigerant Does Not Circulate
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Refrigerant overcharged or insufficient cooling of condenser
  
  Fig 12: Inspecting Refrigerant Pressure With Manifold Gauge Set - Refrigerant Overcharged Or Insufficient Cooling Of Condenser
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 13: Symptom Table - Refrigerant Overcharged Or Insufficient Cooling Of Condenser
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
7. Air present in refrigeration system
  
  Fig 14: Inspecting Refrigerant Pressure With Manifold Gauge Set - Air Present In Refrigeration System
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 15: Symptom Table - Air Present In Refrigeration System
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
8. Expansion valve improperly
  
  Fig 16: Inspecting Refrigerant Pressure With Manifold Gauge Set - Expansion Valve Improperly (Insufficient Cooling)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 17: Symptom Table - Expansion Valve Improperly (Insufficient Cooling)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
9. Defective compression compressor
  
  Fig 18: Inspecting Refrigerant Pressure With Manifold Gauge Set - Defective Compression Compressor
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 19: Symptom Table - Defective Compression Compressor
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT IDLE-UP SPEED
1. Warm up engine.
2. Inspect idle-up speed when the these conditions are established.
  Test conditions:
  - Blower speed control switch at "HI" position
  - Temperature control dial at "COOL" position
  - A/C switch ON
  - Put gear shift in neutral
    
    Fig 20: Magnetic Clutch Condition & Idle Speed Table
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  If idle speed is not as specified, check the idle control system.
INSPECT FOR LEAKAGE OF REFRIGERANT
1. Perform in these conditions.
  - Stop engine
  - Secure good ventilation (If the gas leak detector may not react volatile gases which are not refrigerant, such as evaporated gasoline and exhaust gas)
  - Repeat the test 2 or 3 times
  - Make sure that there is some refrigerant remaining in the refrigeration system.
    When compressor is OFF: approx. 392 - 588 kPa (4 - 6 kgf.cm ² , 57 - 85 psi)
2. Bring the gas leak detector close to the drain hose before performing the test.
  HINT:
  - After the blower motor has stopped, leave the cooling for more than 15 minutes.
  - Expose the gas leak detector sensor under the drain hose.
  - When bring the gas leak detector close to the drain hose, make sure that the gas leak detector does not react to the volatile gases.
  If such reaction is unavoidable, the vehicle must be lifted up.
3. If gas leak is not detected on the drain hose, remove the blower resistor from the cooling unit. Then insert the gas leak detector sensor into the unit and perform the test.
4. Disconnect the connector and leave the pressure switch for approx. 20 minutes. Then bring the gas leak detector close to the pressure switch and perform the test.
5. Bring the gas leak detector close to the refrigerant lines.