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 GS 300FACTORY OEM SERVICE PROCEDURE
Multiplex Communication System DTCS
MULTIPLEX COMMUNICATION SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) INDENTIFICATION
| DTC | Description |
|---|---|
| B1211/11 | Driver Door ECU Communication Stopped |
| B1212/12 | Front Passenger Door ECU Communication Stopped |
| B1213/13 | Tilt & Telescopic ECU Communication Stopped |
| B1214/14 | Door System Communication Bus Malfunction (Short To Voltage) |
| B1215/15 | Door System Communication Bus Malfunction (Short To Ground) |
| B1216/16 | Rear Right Door ECU Communication Stopped |
| B1217/17 | Rear Left Door ECU Communication Stopped |
| B1218/18 | Body ECU No. 2 Communication Stopped |
| B1221/21 | Power Window Switch Circuit On Driver Door |
| B1222/22 | Door Lock Switch Circuit On Driver Door |
| B1223/23 | Power Window Switch Circuit On Passenger Door |
| B1224/24 | Door Lock Switch Circuit On Passenger Door |
| B1225/25 | Power Window Switch Circuit On Rear Right Door |
| B1226/26 | Power Window Switch Circuit On Rear Left Door |
| B1231/31 | Jam Protection Limit Switch Circuit On Driver Door |
| B1232/32 | Jam Protection Pulse Switch Circuit On Driver Door |
| B1233/33 | Jam Protection Limit Switch Circuit On Passenger Door |
| B1234/34 | Jam Protection Pulse Switch Circuit On Passenger Door |
| B1235/35 | Jam Protection Limit Switch Circuit On Rear Right Door |
| B1236/36 | Jam Protection Pulse Switch Circuit On Rear Right Door |
| B1237/37 | Jam Protection Limit Switch Circuit On Rear Left Door |
| B1238/38 | Jam Protection Pulse Switch Circuit On Rear Left Door |
| B1241/41 | Body ECU No. 1 Switch Circuit Diagnosis |
| B1242/42 | Wireless Door Lock Tuner Circuit Malfunction |
| B1244/44 | Light Sensor Circuit Malfunction |
| B1252/52 | Body ECU No. 2 Switch Circuit Diagnosis |
| B1261/61 | ECM Communication Stop |
| B1262/62 | A/C Amplifier Communication Stop |
| B1266/66 | Instrument Panel System Communication Bus Malfunction (Short To Voltage) |
| B1267/67 | Instrument Panel System Communication Bus Malfunction (Short To Ground) |
| B1271/71 | Instrument Panel ECU Communication Stopped |
| B1272/72 | Power Seat ECU Communication Stopped (W/ Seat Memory Only) |
| B1273/73 | Moon Roof ECU Communication Stopped |
| B1275/75 | Accessory Bus Buffer Communication Stopped |
| B1281/81 | Air Bag Sensor Assembly Communication Stopped |
| B1285/85 | Steering Pad Switch Communication Stopped |
| B1293/93 | Gateway ECU Communication Stopped |
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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