Contents Wiring diagrams Section: Communication Devices All sections

Multiplex Control Systems: Diagnosis Lexus RX I

SELF-DIAGNOSTICS

WARNINGDeactivate air bag system before performing any service operation. See AIR BAG RESTRAINT SYSTEMS article. DO NOT apply electrical power to any component on steering column without first deactivating air bag system. Air bag may deploy.

When diagnosing multiplex control system, perform BODY CONTROL ECU and OPEN DOOR INDICATOR LIGHT inspection procedures first to ensure DTCs can be retrieved. See PRELIMINARY INSPECTION .

Scan Tool Method

Multiplex self-diagnostic system OBD-II DTCs are retrieved through Data Link Connector 3 (DLC3). DLC3 is located under left side of instrument panel. Connect scan tool to DLC3. Turn ignition on. Follow LEXUS or OBD-II scan tool instructions to retrieve DTCs. See MULTIPLEX DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS table. If DTC(s) are present, perform appropriate test. See DIAGNOSTIC TESTS .

OBD-II DTC/2-Digit DTCDescription
B1211/11Driver's Door ECU To Body ECU Communication
B1212/12Passenger's Front Door ECU To Body ECU Communication
B1214/14Door System Bus Communication Circuit Short To Power
B1215/15Door System Bus Communication Circuit Short To Ground
B1216/16Right Rear Door ECU To Body ECU Communication
B1217/17Left Rear Door ECU To Body ECU Communication
B1221/21(1) Power Window Master Switch Circuit
B1222/22(1) Driver's Door Lock Control Switch Circuit
B1223/23(1) Passenger's Front Window Switch Circuit
B1224/24(1) Passenger's Door Lock Control Switch Circuit
B1225/25(1) Right Rear Window Switch Circuit
B1226/26(1) Left Rear Window Switch Circuit
B1231/31Driver's Jam Protection Limit Switch Circuit
B1232/32Driver's Jam Protection Pulse Switch Circuit
B1233/33Passenger's Front Jam Protection Limit Switch Circuit
B1234/34Passenger's Front Jam Protection Pulse Switch Circuit
B1235/35Right Rear Jam Protection Limit Switch Circuit
B1236/36Right Rear Jam Protection Pulse Switch Circuit
B1237/37Left Rear Jam Protection Limit Switch Circuit
B1238/38Left Rear Jam Protection Pulse Switch Circuit
B1241/41Body ECU Switch Circuit Diagnosis
B1242/42Wireless Door Lock Tuner Circuit Malfunction
B1244/44Light Sensor Circuit Malfunction
B1256/56Instrument Control Panel Circuit Diagnosis
B1261/61ECM To Body ECU Communication
B1272/72Memory Power Seat ECU To Body ECU Communication
B1273/73Sliding Roof Control ECU To Body ECU Communication
B1275/75Accessory Bus Buffer To Body ECU Communication
B1276/76A/C And Combination Meter Integrated ECU To Body ECU Communication
B1277/77Instrument Control Panel To Body ECU Communication
(1) DTC is not a malfunction. DTC displays switch function. If DTC is not displayed when switch is operated, failure in switch contact exists. If DTC is displayed when switch is not operated, switch is stuck.
(1)DTC is not a malfunction. DTC displays switch function. If DTC is not displayed when switch is operated, failure in switch contact exists. If DTC is displayed when switch is not operated, switch is stuck.

MULTIPLEX DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

CLEARING DIAGNOSTIC TROUBLE CODES

Note. DTCs will be cleared from memory when DTC is normally retrieved.

DIAGNOSTIC TESTS

WARNINGDeactivate air bag system before performing any service operation. See AIR BAG RESTRAINT SYSTEMS article. DO NOT apply electrical power to any component on steering column without first deactivating air bag system. Air bag may deploy.