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.
2005 Lexus IS 300 Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Multiplex Communication System DTCS
MULTIPLEX COMMUNICATION SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC | Description |
|---|---|
| DTC B1211 / 11 | Power window master switch ECU communication stop |
| DTC B1214 / 14 | Communication bus malfunction (+B short) DTC B1215 / 15 Communication bus malfunction (GND short) |
| DTC B1241 / 41 | Body ECU switch circuit diagnosis |
| DTC B1242 / 42 | Wireless door lock tuner circuit malfunction |
| DTC B1244 / 44 | Light sensor circuit malfunction |
| DTC B1261 / 61 | ECM communication stop |
| DTC B1262 / 62 | A/C ECU communication stop |
| DTC B1269 / 69 | Theft deterrent ECU communication stop |
| DTC B1271 / 71 | Combination meter ECU communication stop |
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.