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.
1992 Lexus SC 400FACTORY OEM SERVICE PROCEDURE
Cooling Fan ECU
- Disconnect negative battery cable. Turn ignition off and wait 20 seconds. Remove cover under instrument panel. Remove lower instrument panel cover and glove box door assembly. Disconnect cooling fan ECU.
- Reconnect negative battery cable. Using a DVOM, measure resistance and voltage as indicated in COOLING FAN ECU SPECIFICATIONS table. Make all measurements from harness side of connector. Repair harness as necessary.
COOLING FAN ECU SPECIFICATIONS
| Terminals | Condition | Value | ||
|---|---|---|---|---|
| 1 & Ground | Ignition On | Battery Voltage | ||
| 2 & 3 | (1) 68°F (20°C) | Approx. 8 Ohms | ||
| 4 & Ground | N/A | Continuity | ||
| 5 & Ground | Throttle Open | No Continuity | ||
| 5 & Ground | Throttle Closed | Continuity | ||
| 9 & 10 | (1) 176°F (80°C) | 1.48-1.58 k/Ohms | ||
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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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