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 IS 300 Base, AutomaticFACTORY OEM SERVICE PROCEDURE
HVAC DTCS
HVAC DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC | Description |
|---|---|
| B1411 | Room Temperature Sensor Circuit |
| B1412 | Ambient Temperature Sensor Circuit |
| B1413 | Evaporator Temperature Sensor Circuit |
| B1421 | Solar Sensor Circuit |
| B1422 | Compressor Lock Sensor Circuit |
| B1423 | Pressure Switch Circuit |
| B1431 | Air Mix Damper Position Sensor Circuit |
| B1432 | Air Inlet Damper Position Sensor Circuit |
| B1433 | Air Outlet Damper Position Sensor Circuit |
| B1441 | Air Mix Damper Control Servomotor Circuit |
| B1442 | Air Inlet Damper Control Servomotor Circuit |
| B1443 | Air Outlet Damper Control Servomotor 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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