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.
1999 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Multiplex Control DTCS
MULTIPLEX DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC | Description |
|---|---|
| B1211/11 | No Communication Between Driver's Door ECU & Body ECU |
| B1212/12 | No Communication Between Passenger's Front Door ECU & Body ECU |
| B1213/13 | No Communication Between Tilt & Telescopic ECU & Body ECU |
| B1214/14 | Door System Bus Communication Circuit Is Shorted To Battery Voltage |
| B1215/15 | Door System Bus Communication Circuit Is Shorted To Ground |
| B1216/16 | No Communication Between Right Rear Door ECU & Body ECU |
| B1217/17 | No Communication Between Left Rear Door ECU & Body ECU |
| B1221/21 | Power Window Master Switch Circuit |
| B1222/22 | Driver's Door Lock Control Switch Circuit |
| B1223/23 | Passenger's Front Window Switch Circuit |
| B1224/24 | Passenger's Door Lock Control Switch Circuit |
| B1225/25 | Right Rear Window Switch Circuit |
| B1226/26 | Left Rear Window Switch Circuit |
| B1231/31 | Driver's Jam Protection Limit Switch Circuit |
| B1232/32 | Driver's Jam Protection Pulse Switch Circuit |
| B1233/33 | Passenger's Front Jam Protection Limit Switch Circuit |
| B1234/34 | Passenger's Front Jam Protection Pulse Switch Circuit |
| B1235/35 | Right Rear Jam Protection Limit Switch Circuit |
| B1236/36 | Right Rear Jam Protection Pulse Switch Circuit |
| B1237/37 | Left Rear Jam Protection Limit Switch Circuit |
| B1238/38 | Left Rear Jam Protection Pulse Switch Circuit |
| B1241/41 | Body ECU Switch Circuit Diagnosis |
| B1242/42 | Wireless Door Lock Tuner Circuit Malfunction |
| B1243/43 | GSW Terminal Circuit Malfunction |
| B1244/44 | Light Sensor Circuit Malfunction |
| B1261/61 | No Communication Between ECM & Body ECU |
| B1262/62 | No Communication Between A/C Control Assembly & Body ECU |
| B1266/66 | Instrument Panel System Bus Communication Circuit Is Shorted To Battery Voltage |
| B1267/67 | Instrument Panel System Bus Communication Circuit Is Shorted To Ground |
| B1271/71 | No Communication Between Combination Meter ECU & Body ECU |
| B1272/72 | No Communication Between Power Seat ECU (W/Memory) & Body ECU |
| B1273/73 | No Communication Between Sun Roof Control Relay & Body ECU |
| B1275/75 | No Communication Between Accessory Bus Buffer & Body ECU |
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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