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 COMPRESSOR FOR METALLIC SOUND
1. Start engine.
2. Check there is abnormal metallic sound from the compressor when the A/C switch is ON.
If abnormal sound is heard, replace the compressor assembly.
INSPECT REFRIGERANT PRESSURE (See ON-VEHICLE INSPECTION )
INSPECT COMPRESSOR LOCK SENSOR RESISTANCE
1. Disconnect the connector.
2. Measure resistance between terminals 1 and 2.
  1. Standard resistance: 65-125 +/- at 20°C (68°F)
  If resistance is not as specified, replace the compressor assembly.
INSPECT VISUAL FOR LEAKAGE OF REFRIGERANT FROM SAFETY SEAL

Fig 1: Checking Compressor Lock Sensor Resistance
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Using a gas leak detector, check for leakage of refrigerant. If there is any leakage, replace the compressor assembly.
MAKE THESE VISUAL CHECKS:
1. Leakage of grease from the clutch bearing.
2. Signs of oil on the pressure plate If necessary repair or replace.
INSPECT MAGNETIC CLUTCH BEARING FOR NOISE
1. Start engine.
2. Check for abnormal noise near the compressor when the A/C switch is OFF.
If abnormal noise is being emitted, replace the magnetic clutch.
INSPECT MAGNETIC CLUTCH OPERATION
1. Disconnect the connector.
2. Connect the positive (+) lead from the battery to terminal
  4 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: Checking Magnetic Clutch Operation
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002