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HOMESERVICE MANUALSTOYOTA2004CELICA GT, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 345 (ENGINE CONTROL SYSTEM - DIAGNOSIS)ACTIVE CONTROL ENGINE MOUNTINSPECTION PROCEDURE
2004 Toyota Celica GT, Standard

Inspection Procedure

2004 Toyota Celica GT, StandardSECTION Inspection Procedure
WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK VACUUM HOSES 
    1. Check whether the cap of vacuum hose is missing or not.
    2. If the hose is damaged, replace the vacuum hose assembly.
    3. Check the air and vacuum hoses for looseness, disconnection and blockage.
      Fig 1: Checking Air And Vacuum Hoses For Looseness, Disconnection And Blockage
      G01438616Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE VACUUM HOSES 

    OK: GO TO NEXT STEP. 

  2. CHECK VACUUM 
    1. Start the engine.
    2. Disconnect the vacuum hose from the vacuum tank.
    3. Check that an unconnected port located on the vacuum tank applies suction to your finger.
    4. Reconnect the vacuum hose.
      Fig 2: Disconnecting Vacuum Hose From Vacuum Tank
      G01438617Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: CHECK AND REPLACE VACUUM SOURCE AND HOSES 

    OK: GO TO NEXT STEP. 

  3. INSPECT ECM 
    1. Connect the oscilloscope between terminals ACM and of the E8 ECM connector.
    2. Warm up the engine to normal operating temperature.
    3. Turn the A/C switch ON.
    4. Measure the voltage between terminals ACM and E1 of the E8 ECM connector.

      Result: 

      Fig 3: ECM Connector Terminals Voltage Chart
      G01438618Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
RENDER: 1.0x

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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.