Inspection Procedure

WARNING: This page is about a different car, the 2004 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT ECM (LCKI)
1. Remove ECM with the connectors being connected.
2. Start the engine.
3. Operate the A/C system.
4. Check the signal waveform between terminal LCKI of ECM and body ground.
  Standard:
  
  The correct waveform appears as shown in the illustration.
Fig 2: Checking Signal Waveform Between Terminal LCKI Of ECM And Body Ground
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go To Step 6

NG: Go To Next Step.
CHECK COOLER COMPRESSOR ASSY
1. Check and adjust the compressor drive belt tension (See ADJUSTMENT ).
2. Check if the cooler compressor assy does not lock while running the engine and operating the A/C system.
  Standard: Cooler compressor assy does not lock during the operation.
NG: REPLACE COOLER COMPRESSOR ASSY

OK: Go To Next Step.
INSPECT COOLER COMPRESSOR ASSY (COMPRESSOR LOCK SENSOR)

Fig 3: Inspecting Cooler Compressor Assy (Compressor Lock Sensor)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Disconnect the cooler compressor assy connector.
2. Measure resistance between terminal 1 and 2 of the cooler compressor assy connector.
  Resistance: at 20°C (68°F): 165-205 Ω
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go To Next Step.
CHECK HARNESS AND CONNECTOR (BETWEEN ECM AND AIR CONDITIONING AMPLIFIER)
1. Check for open and short circuit in the harness and the connector between the cooler compressor assy and the A/C amplifier (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: GO TO NEXT STEP
CHECK HARNESS AND CONNECTOR (BETWEEN COOLER COMPRESSOR ASSY AND BODY GROUND)
1. Check for open and short circuit in the harness and the connector between the cooler compressor assy and body ground (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: CHECK AND REPLACE ECM
INSPECT ECM (ACLD)
1. Remove ECM with the connectors being connected.
2. Operate A/C system.
3. Measure voltage between terminal ACLD of ECM and body ground under each condition.
  
  Fig 4: Inspecting ECM (ACLD)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Voltage:
  
  Magnetic clutch is engaged: Below 1.0 V
  
  Magnetic clutch is not engaged: 10-14 V
NG: CHECK AND REPLACE ECM

OK: Go To Next Step.

INSPECT AIR CONDITIONING AMPLIFIER (ACLD)

Remove the A/C amplifier assy with the connectors being connected.
Operate the A/C system.
Measure voltage between terminal ACLD of the A/C amplifier assy and body ground under each condition.

Fig 5: Inspecting Air Conditioning Amplifier (ACLD)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Voltage:

Magnetic clutch is engaged: Below 1.0 V

Magnetic clutch is not engaged: 10-14 V

RESULT CHART

A	NG
B	OK (when checking using PROBLEM SYMPTOM TABLE)
C	OK (when checking using DTC)

B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE , refer to PROBLEM SYMPTOMS TABLE

C: CHECK AND REPLACE AIR CONDITIONING AMPLIFIER

A: REPAIR OR REPLACE HARNESS OR CONNECTOR