Inspection Procedure

Check A/C compressor.
PREPARATION:
1. Check the tension of the compressor drive belt (See INSPECT DRIVE BELT'S INSTALLATION CONDITION ).
2. Check if the compressor does not lock during operation with the engine started, and the blower switch and A/C switch ON.
1. NG : Adjust drive belt tension or repair compressor (See INSPECT DRIVE BELT'S INSTALLATION CONDITION ).
2. OK : Go to Next Step
Check A/C compressor lock sensor (See ON-VEHICLE INSPECTION ).
Reference: INSPECTION USING OSCILLOSCOPE

During cranking or idling, check the waveform between terminals LCKI and E1 of the ECM connector.

HINT:

The correct waveform appears as shown.

Fig 1: Checking Waveform Between Terminals LCK1 & E1 Of ECM Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace compressor lock sensor (See COMPONENTS ).
2. OK : Go to Next Step
Check magnetic clutch relay (Marking: A/C COMP) (See INSPECTION ).
1. NG : Replace magnetic clutch relay (See COMPONENTS ).
2. OK : Go to Next Step
Check harness and connector between A/C compressor lock sensor and ECM (See PROCEDURE ).
1. NG : Repair or replace harness and connector.
2. OK : Check and replace ECM (See PROCEDURE ).