Inspection Procedure

WARNING: This page is about a different car, the 2005 Lexus GS 430 and 2005 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminal ACMG of ECM.

CHECK:

Start the engine.
Push AUTO SW.
Measure voltage between terminal ACMG of ECM connector and body ground when A/C switch is ON and OFF.

Fig 1: Measuring Voltage Between AC MG Terminal Of ECM Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK:

A/C SWITCH VOLTAGE REFERENCE CHART

A/C switch	Voltage
ON	10 - 14 V
OFF	0 V

RESULT:

RESULT

A	OK
B	Remains between 10 and 14 V
C	Remains 0 V

B: Go to step 5 .
C: Go to step 4 .
A: Go to next step.

Check A/C compressor magnetic clutch.
PREPARATION:

Disconnect magnetic clutch connector.

CHECK:

Connect positive (+) lead connected to battery to magnetic clutch connector terminal 3.

OK:

Magnetic clutch is energized.

Fig 2: Connecting (+VE) Lead To Battery To Magnetic Clutch Connector Terminal 3
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Repair A/C compressor magnetic clutch.
2. OK: Go to next step.
Check harness and connector between A/C compressor and compressor relay (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE )
1. NG: Repair or replace harness or connector.
2. OK: Go to next step.
Check harness and connector between compressor relay and ECM (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).
1. NG: Repair or replace harness or connector.
2. OK: Go to next step.
Check harness and connector between ECM and A/C compressor assembly (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).
1. NG: Repair or replace harness or connector.
2. OK: Check and replace ECM and/or A/C control assembly.