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.
1997 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Circuit Test
- Under left side of instrument panel, remove trim panel, key cylinder pad and duct, as necessary, to access junction block. Remove set bolts and clamp securing junction block. Separate tilt/telescopic ECU from junction block.
- Remove wiring harness clamp. Lower junction block. Disconnect 12-pin connector from body control ECU, located above junction block. Place shift lever in Neutral (or depress clutch pedal). While holding ignition switch in START position, measure voltage between body ground and terminal No. 2 of body control ECU. See Fig 1.
- If 10-14 volts is measured, replace body control ECU. If 10-14 volts is not measured, check for faulty starter relay, park/neutral position switch (clutch switch on M/T), or wiring harness.
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.
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