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.
1998 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Control Units
CONTROL UNITS
| Component | Component Location |
|---|---|
| AB, TRAC & VSC ECU | Behind right side of dash. See Figure. |
| A/C Control Assembly | Behind center of dash. See Figure. |
| Air Bag Sensor Assembly | Behind front of center console. See Figure. |
| Air Suspension ECU | Behind right side of dash. See Figure. |
| Blower Controller | Behind right side of dash. |
| Body ECU | Behind left side of dash. See Figure. |
| Driver Door ECU | In driver's door. See Figure. |
| Engine Control Module | Behind right side of dash. See Figure. |
| Headlight Beam Level Control ECU | Behind right side of dash. See Figure. |
| Headlight Control ECU (High Beam) (Left) | Behind left headlight. See Figure. |
| Headlight Control ECU (High Beam) (Right) | Behind right headlight. See Figure. |
| Headlight Control ECU (Low & High Beam) (Left) | Behind left headlight. See Figure. |
| Headlight Control ECU (Low & High Beam) (Right) | Behind right headlight. See Figure. |
| Navigation ECU | At left rear corner of luggage compartment. See Figure. |
| Passenger Door ECU | In right front door. See Figure. |
| Power Seat ECU | Under driver's seat. |
| PPS ECU | Behind left side of dash. See Figure. |
| Rear Door ECU (Left) | In left rear door. See Figure. |
| Rear Door ECU (Right) | In right rear door. See Figure. |
| Shift Lock ECU | Under center console, near selector lever. See Figure. |
| Tilt & Telescopic ECU | Behind left side of dash. See Figure. |
| Wireless Door Lock Control ECU | Behind right side of dash. See Figure. |
Factory Service Tools
Use the Manual With the Right Hardware
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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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