Engine Coolant Temperature (ECT) Switch: Inspection

2004 Toyota Matrix XR, FWD, StandardSECTION Inspection
WARNING: This page is about a different car, the 2002 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove Engine Under Cover 
  2. Drain Engine Coolant From Radiator 

    HINT:

    It is not necessary to drain out all coolant

  3. Remove Engine Coolant Temperature Switch 
    1. Disconnect the connector.
    2. Remove the engine coolant temperature switch.
    3. Remove the O-ring from the switch.
    Fig 1: Disconnecting Engine Coolant Temperature Switch Connector
    G01179090Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Inspect Engine Coolant Temperature Switch 
      Fig 2: Checking Coolant Temperature Switch For Continuity
      G01179091Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Using an ohmmeter, check that no continuity exists between the terminals when the coolant temperature i' above 100 °C (212 °F).

      If continuity exists, replace the switch.

    2. Using an ohmmeter, check that continuity exists between the terminals when the coolant temperature is below 91 °C (196°F).

      If there no continuity exists, replace the switch.

  5. Install Engine Coolant Temperature Switch 
    1. Install the new O-ring to the switch.
    2. Install the engine coolant temperature switch.

      Torque: 7.4 N.m (75 kgf.cm, 65 in.lbf) 

  6. Fill With Engine Coolant To Radiator 
  7. Install Engine Under Cover 
RENDER: 1.0x

NO RELATED

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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.