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.
2003 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 |
| B1422/22 | COMPRESSOR LOCK SENSOR CIRCUIT |
| B1423/23 | PRESSURE SWITCH CIRCUIT |
| B1424/24 | SOLAR SENSOR CIRCUIT (DRIVER SIDE) |
| 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 DAMPER CONTROL SERVOMOTOR CIRCUIT (PASSENGER SIDE) |
| B1442/42 | AIR INLET DAMPER CONTROL SERVOMOTOR CIRCUIT |
| B1443/43 | AIR OUTLET DAMPER CONTROL SERVOMOTOR CIRCUIT |
| B1446/46 | AIR MIX DAMPER CONTROL SERVOMOTOR 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.
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