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.
2012 Lexus IS 250C Automatic TransFACTORY OEM SERVICE PROCEDURE
Multiplex Communication System
MULTIPLEX COMMUNICATION SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC Code | Description |
|---|---|
| B1200 | MPX Body ECU Stop |
| B1206 | P/W Master Switch Communication Stop |
| B1207 | Smart ECU Stop |
| B1208 | Passenger Side Outer Mirror ECU |
| B1209 | Driver Side Outer Mirror |
| B1210 | Power ECU Stop |
| B1212 | Front Passenger Door ECU Communication Stop |
| B1213 | Tilt and Telescopic ECU Communication Stop |
| B1214 | Short to B+ in Door System Communication Bus Malfunction |
| B1215 | Short to GND in Door System Communication Bus Malfunction |
| B1247 | Tire Pressure Monitor Receiver Communication Stop |
| B1248 | AVC-LAN Communication Impossible |
| B1262 | A/C ECU Communication Stop |
| B1266 | Short to B+ in Instrument Panel System Communication Bus Malfunction |
| B1267 | Short to GND in Instrument Panel System Communication Bus Malfunction |
| B1271 | Combination Meter ECU Communication Stop |
| B1272 | Power Seat ECU Communication Stop |
| *5 B1273 |
Sliding Roof ECU Communication Stop |
| B1278 | Combination Switch ECU Communication Stop |
| B1279 | Rain Sensor Communication Stop |
| B1280 | Left Side Junction Block ECU Communication Stop |
| B1289 | Passenger Seat ECU Communication Stop |
| B1296 | Front Light ECU Communication Stop |
| B1297 | Clearance Sonar ECU Communication Stop |
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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