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.
2002 Lexus SC 430FACTORY OEM SERVICE PROCEDURE
HVAC DTCS
HVAC DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC | Description |
|---|---|
| B1411/11 | Room temperature sensor circuit |
| B1412/12 | Ambient temperature sensor circuit |
| B1413/13 | Evaporator temperature sensor circuit |
| B1418/18 | Exhaust gas sensor circuit |
| B1421/21 | Solar sensor circuit (short) |
| Solar sensor circuit (open) | |
| B1422/22 | All conditions below are detected for 3 sec. or more (a) Engine speed: 450 RPM or more (b) Ratio between engine and compressor RPM deviates 20 % or more in comparison to normal operation. |
| B1423/23 | Pressure switch circuit |
| B1424/24 | Solar sensor circuit (short) |
| Solar sensor circuit (open) | |
| B1431/31 | Air mix damper position sensor circuit (Passenger side) |
| B1432/32 | Air inlet damper position sensor circuit |
| B1433/33 | Air outlet damper position sensor circuit |
| B1436/36 | Air mix damper position sensor circuit (Driver side) |
| B1441/41 | Air mix control servo motor circuit (Passenger side) |
| B1442/42 | Air inlet damper control servo motor circuit |
| B1443/43 | Air outlet control servo motor circuit |
| B1446/46 | Air mix damper control servo motor circuit (Driver side) |
| B1499/99 | Multiplex communication circuit |
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.