2004 Toyota MR2 C56FACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. 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 
  2. 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
    G02913943Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG : Replace compressor lock sensor (See  COMPONENTS  ). 
    2. OK : Go to Next Step 
  3. Check magnetic clutch relay (Marking: A/C COMP) (See  INSPECTION  ). 
    1. NG : Replace magnetic clutch relay (See  COMPONENTS  ). 
    2. OK : Go to Next Step 
  4. 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  ). 
Factory Service Tools

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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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