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.
1990 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Control Units
CONTROL UNITS LOCATION
| Component | Location | |
|---|---|---|
| Electronic Control Unit (ECU) | ||
| A/C System | Behind center of dash. See Figure. | |
| Anti-Lock Brakes (ABS) | Behind right side of dash. See Figure & Figure . | |
| Anti-Theft | Behind left side of dash. See Figure. | |
| Coolant Level Warning | Behind left side of dash, left of steering column. See Figure. | |
| Cruise Control | Behind left side of dash. See Figure & Figure . | |
| Elec. Modulated Air Suspension | In right rear corner of luggage compartment. See Figure. | |
| Elec. Side Mirrors | Behind right side of dash. See Figure. | |
| Engine | Behind right side of dash. See Figure, Figure & Figure . | |
| Power Seat | Under driver's seat. See Figure. | |
| Progressive Power Steering | Behind center of dash. See Figure. | |
| SRS System | Behind center console. See Figure & Figure . | |
| Shift Lock (A/T) | On center console, behind shift lever. See Figure. | |
| TRAC System | Behind right side of dash, integral of ABS ECU. See Figure & Figure . | |
| Tilt & Telescopic Steering Column | Behind left side of dash, above steering column. See Figure. | |
| Transmission | Behind right side of dash, integrated with engine ECU. See Figure, Figure & Figure . | |
| Wireless Door Lock | On left side of luggage compartment. | |
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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