On-Vehicle Inspection

WARNING: This page is about a different car, the 2004 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT COMPRESSOR FOR METALLIC SOUND
Check there is abnormal metallic sound from the compressor when the A/C switch is ON.

If abnormal metallic sound is heard, replace the compressor assembly.
INSPECT REFRIGERANT PRESSURE (See ON-VEHICLE INSPECTION )
INSPECT VISUALLY FOR LEAKAGE OF REFRIGERANT
Using a gas leak detector, check for leakage of refrigerant. If there is any leakage, replace the compressor assembly.
INSPECT COMPRESSOR LOCK SENSOR RESISTANCE
1. Disconnect the connector.
2. Measure resistance between terminal 1 and 2.
  Standard resistance:
  
  570 - 1,050 Ω at 20°C (68°F)
If resistance is not as specified, replace the compressor.

Fig 1: Inspecting Compressor Lock Sensor Resistance
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
MAKE THESE VISUAL CHECKS:
1. Leakage of grease from the clutch bearing.
2. Signs of oil on the pressure plate or rotor.
INSPECT MAGNETIC CLUTCH BEARING FOR NOISE
1. Start engine.
2. Check for abnormal noise from the compressor when the A/C switch is OFF.
If abnormal noise is emitted, replace the rotor of magnetic clutch.
INSPECT MAGNETIC CLUTCH OPERATION
1. Disconnect the connector.
2. Connect the positive (+) lead from the battery to terminal 3 and the negative (-) lead to the body ground.
3. Check that the magnetic clutch is energized.
If operation is not as specified, replace the magnetic clutch.

Fig 2: Inspecting Magnetic Clutch Operation
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002