Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Inspection Procedure
- Check A/C compressor.
PREPARATION:
- Check the tension of the compressor drive belt (See INSPECT DRIVE BELT'S INSTALLATION CONDITION ).
- 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 INSPECT DRIVE BELT'S INSTALLATION CONDITION ).
- 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.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- 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 COMPONENTS ).
- OK : Go to Next Step
- Check harness and connector between A/C compressor lock sensor and ECM (See PROCEDURE
).
- NG : Repair or replace harness and connector.
- OK : Check and replace ECM (See PROCEDURE ).
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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