Inspection Procedure

Check A/C compressor.
PREPARATION:
1. Check the tension of the compressor drive belt (See DRIVE BELT ).
2. Check if the compressor does not lock during operation with the engine started, and the blower switch and A/C switch ON.
- NG: Adjust drive belt tension or repair compressor (See DRIVE BELT ).
- OK: Go to next step.
Check A/C compressor lock sensor (See COMPRESSOR AND MAGNETIC CLUTCH ).
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 in Fig 1.

Fig 1: Identifying LCKI Signal Waveform
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- NG: Replace compressor lock sensor (See COMPONENTS ).
- OK: Go to next step.
Check magnetic clutch relay (Marking: A/C COMP) (See INSPECTION ).
- NG: Replace magnetic clutch relay (See MAGNETIC CLUTCH RELAY ).
- OK: Go to next step.
Check harness and connectors between A/C compressor lock sensor and ECM (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).
- NG: Repair or replace harness or connector.
- OK: Replace ECM (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).