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 GS 300FACTORY OEM SERVICE PROCEDURE
Multiplex Communication System DTCS
MULTIPLEX COMMUNICATION SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC | Description |
|---|---|
| DTC B1211 / 11 | Driver door ECU communication stop |
| DTC B1212 / 12 | Front passenger door ECU communication stop |
| DTC B1213 / 13 | Tilt and telescopic ECU communication stop |
| DTC B1214 / 14, DTC B1215 / 15 | Door system communication bus malfunction (+B short)/(GND short) |
| DTC B1216 / 16 | Rear right door ECU communication stop |
| DTC B1217 / 17 | Rear left door ECU communication stop |
| DTC B1218 / 18 | Body ECU No. 2 communication stop |
| DTC B1221 / 21, B1222 / 22, B1223 / 23, B1224 / 24, B1225 / 25, B1226 / 26, B1241 / 41, B1252 / 52 | Power window/door lock switch circuit on driver/passenger door, Power window switch circuit on rear right/rear left door, Body No. 1/No. 2 ECU switch circuit diagnosis |
| DTC B1231 / 31, B1232 / 32, B1234 / 34, B1236 / 36, B1238 / 38 | Jam protection limit/pulse switch circuit on driver door, Jam protection pulse switch circuit on passenger/rear right/rear left door |
| DTC B1233 / 33, B1235 / 35, B1237 / 37 | Jam protection limit switch circuit on passenger/rear right/rear left door |
| 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 amplifier communication stop |
| DTC B1266 / 66, B1267 / 67 | Instrument panel system communication bus malfunction (+B short)/(GND short) |
| DTC B1271 / 71 | Combination meter ECU communication stop |
| DTC B1272 / 72 | Power seat ECU communication stop (w/ Seat memory vehicle only) |
| DTC B1273 / 73 | Sliding roof ECU communication stop (w/ Sliding roof vehicle only) |
| DTC B1281 / 81 | Airbag sensor assembly communication stop |
| DTC B1285 / 85 | Steering pad switch communication stop (GS 430 only) |
| DTC B1293 / 93 | Gateway 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.
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