Inspection Procedure

WARNING: This page is about a different car, the 2003 Lexus IS 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.

OK:

TERMINAL ACMG OF ECM CONNECTOR AND BODY GROUND VOLTAGE SPECIFICATION

A/C switch	Voltage
ON	10 - 4 V
OFF	0 V

Fig 1: Checking Voltage Between Terminal ACMG Of ECM

OK: Check and replace ECM and/or A/C amplifier.
NG: 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.

OK:

Magnetic clutch is energized.

Fig 2: Checking A/C Compressor Magnetic Clutch
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 (INSPECTION, Connectors, Terminal pins, Wiring Harness (Open or Short Circuits)).
1. NG: Repair or replace harness or connector.
2. OK: Go to next step.
Check harness and connector between compressor relay and ECM (INSPECTION, Connectors, Terminal pins, Wiring Harness (Open or Short Circuits)).
1. NG: Repair or replace harness or connector.
2. OK: Go to next step.
Check harness and connector between ECM and A/C amplifier (INSPECTION, Connectors, Terminal pins, Wiring Harness (Open or Short Circuits)).
1. NG: Repair or replace harness or connector.
2. OK: Check and replace ECM and/or A/C amplifier.