2007 Lexus SC 430FACTORY OEM SERVICE PROCEDURE

Monitor Description

Fig 1: Thermostat Malfunction Diagram
G05291339Courtesy of Β© TOYOTA, LICENSE AGREEMENT TMS1002

The ECM estimates the coolant temperature based on starting temperature, engine loads, and engine speeds. The ECM then compares the estimated temperature with the actual ECT. When the estimated coolant temperature reaches 75Β°C (167Β°F), the ECM checks the actual ECT. If the actual ECT is less than 75Β°C (167Β°F), the ECM will interpret this as a fault in the engine cooling system or thermostat and set a DTC.

Factory Service Tools

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:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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