On-Vehicle Inspection

WARNING: This page is about a different car, the 2002 Lexus RX 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: Locating Sight Glass
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Problem Symptoms And Remedy Chart
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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.
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 )
  Fig 3: Identifying Manifold Gauge Set Reading For Normally Functioning Of Refrigerant System
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Moisture present in refrigeration system.
  
  Fig 4: Identifying Manifold Gauge Set Reading When Moisture Present In Refrigeration System
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 5: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Insufficient cooling
  
  Fig 6: Identifying Manifold Gauge Set Reading When Insufficient Cooling
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 7: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Poor circulation of refrigerant
  
  Fig 8: Identifying Manifold Gauge Set Reading For Poor Circulation Of Refrigerant
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 9: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Refrigerant does not circulate
  
  Fig 10: Identifying Manifold Gauge Set Reading When Refrigerant Does Not Circulate
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 11: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Refrigerant overcharged or insufficient cooling of condenser
  
  Fig 12: Identifying Manifold Gauge Set Reading When Refrigerant Overcharged Or Insufficient Cooling Of Condenser
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 13: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
7. Air present in refrigeration system
  
  Fig 14: Identifying Manifold Gauge Set Reading When Air Present In Refrigeration System
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 15: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
8. Expansion valve improperly
  
  Fig 16: Identifying Manifold Gauge Set Reading When Expansion Valve Improper
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 17: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
9. Defective compression compressor
  
  Fig 18: Identifying Manifold Gauge Set Reading With Defective Compression Compressor
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 19: Problem Symptoms And Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT IDLE-UP SPEED
1. Warm up engine
2. Connect the tachometer.
3. 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 And Idle-Up Speed Specifications
  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.cm² ), 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.