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.
2003 Lexus LX 470FACTORY OEM SERVICE PROCEDURE
Circuit Opening Relay
- Ensure ignition is off. Remove C/OPN relay from relay box at driver's side front corner of engine compartment, near battery.
- To test C/OPN relay continuity, use ohmmeter to check for continuity and no continuity between specified terminals on C/OPN relay. See Fig 1. If there is no continuity between terminals No. 1 and 2, or there is continuity between terminals No. 3 and 5, replace relay.
- Apply battery positive voltage across terminals No. 1 and 2. Using an ohmmeter, check that there is continuity between terminals No. 3 and 5. See Fig 2. If there is no continuity, replace relay.
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.