On-Vehicle Inspection

WARNING: This page is about a different car, the 2003 Lexus LX 470. 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:
- Engine speed at 1,500 rpm
- Blower speed control switch at "HI" position
- A/C switch ON
- Temperature control dial at "COOL" position
- Doors fully opened
  
  Fig 1: Identifying Sight Glass On Liquid Tube
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Symptoms & Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET
Check the trouble area using a set of manifold gauge set. Read the manifold gauge pressure when following conditions are detected.

Test conditions:
- Temperature at the air inlet with the switch set at RECIRC is 30 - 35 °C (86 - 95 °F)
- Engine speed 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 depending on ambient temperature conditions.
1. Normally functioning refrigeration system.
  Gauge reading:
  
  Low pressure side:
  
  0.15 - 0.25 MPa (1.5 - 2.5 kgf/cm ² )
  
  High pressure side:
  
  1.37 - 1.57 MPa (14 - 15 kgf/cm ² )
  
  Fig 3: Normal Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Moisture present in refrigeration system.
  
  Fig 4: Moisture Present In Refrigeration System Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 5: Moisture Present In Refrigeration System Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Insufficient cooling
  
  Fig 6: Insufficient Cooling Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 7: Insufficient Cooling Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Poor circulation of refrigerant
  
  Fig 8: Poor Circulation Of Refrigerant Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 9: Poor Circulation Of Refrigerant Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Refrigerant does not circulate
  
  Fig 10: Refrigerant Does Not Circulate Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 11: Refrigerant Does Not Circulate Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Refrigerant overcharged or insufficient cooling of condenser
  
  Fig 12: Refrigerant Overcharged Or Insufficient Cooling Of Condenser Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 13: Refrigerant Overcharged Or Insufficient Cooling Of Condenser Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
7. Air present in refrigeration system
  
  Fig 14: Air Present In Refrigeration System Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 15: Air Present In Refrigeration System Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
8. Expansion valve improperly
  
  Fig 16: Expansion Valve Trouble Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 17: Expansion Valve Trouble Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
9. Defective compression compressor
  
  Fig 18: Defective Compression Compressor Manifold Gauge Reading
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 19: Defective Compression Compressor Remedy Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT IDLE-UP SPEED
1. Warm up engine
2. Inspect idle-up speed when following 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: Clutch Condition And Idle-Up Speed Chart
    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 (The gas leak detector may not react to 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 stops, 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 gas leaks are detected, lift up the vehicle.
3. If gas leaks are not detected on the drain hose, remove the blower resistor from the cooling unit. Then insert the gas leak detector sensor into the unit to 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 to perform the test.
5. Bring the gas leak detector close to the refrigerant lines.