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.
Test C: Initial Set Control Function Does Not Operate (Warning Light Lights Up)
2004 Toyota Celica GT, StandardSECTION Test C: Initial Set Control Function Does Not Operate (Warning Light Lights Up)
WARNING: This page is about a different car, the 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- Check the continuity between the vehicle side wiring harness between the headlight leveling ECU and headlight leveling motor. See Fig 1. If there is continuity, go to the next step. If there is not continuity, repair or replace harness or connector.
- Check that the headlight unit (leveling motor) operates normally when lighting up the headlight with the engine running. If the results are OK, check and replace the headlight leveling ECU assembly. See HEADLIGHT ASSEMBLY under REMOVAL & INSTALLATION. If the results are not good, replace the headlight unit (leveling motor).
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.