Multiplex Communication: Overview Lexus RX II facelift

DESCRIPTION

DTC B1205 is output when communication between the headlight swivel ECU (AFS ECU) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE TABLE

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1. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the A14 ECU connector. Disconnect the 3L J/B connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition A14-5 (MPX1) - 3L-7 (MPX1) Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK J/B NO. 3 Disconnect the 3L J/B connector. Disconnect the 3G J/B connector. Check the resistance between the J/B side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition 3L-7 - 3G-2 Below 1 ohms NG: REPLACE J/B NO. 3 OK: Go to next step
3. CHECK HEADLIGHT SWIVEL ECU ASSEMBLY (POWER SOURCE) Disconnect the A14 ECU connector. Check the voltage between the wire harness side connector and the body ground. Voltage TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Switch Position Specified Condition A14-12 (IGS) - Body ground Ignition switch ON 10 to 14 V A14-2 (IG) - Body ground NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
4. CHECK HEADLIGHT SWIVEL ECU ASSEMBLY (GROUND) Disconnect the A14 ECU connector. Check the resistance between the wire harness side connector and the body ground. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition A14-11 (E1S) - Body ground Below 1 ohms A14-1 (E1) - Body ground NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE HEADLIGHT SWIVEL ECU ASSEMBLY

DTC B1206 is output when communication between the power window regulator master switch and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE TABLE

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1. CHECK OPERATION Check that the power window master switch can operate the power window normally. If only the driver side power window can be operated, proceed to A. If all the power windows can not be operated, proceed to B. If all the power windows can be operated, proceed to C. B: GO TO «POWER WINDOW CONTROL SYSTEM»(ref-236041-S31825766862006062900000) C: INTERMITTENT PROBLEMS A: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the P22 switch connector. Disconnect the A8 amplifier connector. Disconnect the C9 meter connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition P22-7 (MPX1) - A8-3 (MPX+) Below 1 ohms P22-8 (MPX2) - C9-4 (MPX-) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY

DTC B1208 is output when communication between the outer mirror control ECU (passenger side) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the outer mirror control switch can operate the outer mirror normally. NG: GO TO «POWER MIRROR CONTROL SYSTEM»(ref-236042-S02487519702006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the R27 ECU connector. Disconnect the 3B J/B connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition R27-6 (MPX1) - 3B-18 (MPX1) Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK J/B NO. 3 Disconnect the 3B and 3K J/B connectors. Check the resistance between the J/B side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition 3B-18 - 3K-18 Below 1 ohms NG: REPLACE J/B NO. 3 OK: REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY (PASSENGER SIDE)

DTC B1209 is output when communication between the outer mirror control ECU (driver side) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the outer mirror control switch can operate the outer mirror normally. NG: GO TO «POWER MIRROR CONTROL SYSTEM»(ref-236042-S02487519702006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the R26 ECU connector. Disconnect the R22 master switch connector. Disconnect the A8 amplifier connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition R26-6 (MPX1) - P22-7 (MPX1) Below 1 ohms R26-6 (MPX1) - A8-3 (MPX+) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY (DRIVER SIDE)

DTC B1213 is output when communication between the multiplex tilt & telescopic ECU and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the power tilt & telescopic switch can operate the tilt & telescopic steering column normally. NG: GO TO «POWER TILT AND POWER TELESCOPIC STEERING COLUMN»(ref-235995-S29196051502006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the T4 multiplex tilt & telescopic ECU connector. Disconnect the A8 amplifier ECU connector. Disconnect the T9 key ECU connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition T4-5 (MPX1) - A8-4 (MPX-) Below 1 ohms T4-14 (MPX2) - T9-4 (MPX1) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE MULTIPLEX TILT & TELESCOPIC ECU

DTCs B1214 and B1215 are output when +B and the body ground is short-circuited on the communication bus. Detecting this condition disables all the BEAN communication and outputs the DTCs.

DIAGNOSTIC TROUBLE CODE CHART

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Note. Disconnect connectors in operational sequence, and start the next operation after the connectors are connected.

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1. CHECK DTC (MULTIPLEX NETWORK BODY ECU - A/C AMPLIFIER) Check whether the output of the DTC when the B5 connector of the body ECU and the A/C amplifier connector are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, there is a malfunction between the B5 connector of the body ECU and the A/C ECU connector. NG: Go to step 14 OK: Go to next step.
2. CHECK DTC (CENTER CLUSTER INTEGRATION SWITCH ASSEMBLY) (W/O NAVIGATION) Check whether the output of the DTC stops when the integration switch connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the integration switch is malfunctioning. NG: Go to step 3 OK: REPLACE CENTER CLUSTER INTEGRATION SWITCH ASSEMBLY
3. CHECK DTC (NETWORK GATEWAY ECU) (W/ LEXUS NAVIGATION SYSTEM) Check whether the output of the DTC stops when the gateway ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the gateway ECU is malfunctioning. NG: Go to step 4 OK: REPLACE NETWORK GATEWAY ECU
4. CHECK WIRE HARNESS (MULTIPLEX NETWORK BODY ECU - SWITCH OR NETWORK GATEWAY ECU) Check whether the output of the DTC stops when the B5 connector of the body ECU, integration switch and the gateway ECU connectors are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the integration switch or gateway ECU and B5 connector of the body ECU are malfunctioning. NG: Go to step 5 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (MULTIPLEX NETWORK BODY ECU - SWITCH OR NETWORK GATEWAY ECU)
5. CHECK DTC (ECM) Check whether the output of the DTC stops when the ECM connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the ECU is malfunctioning. NG: Go to step 6 OK: REPLACE ECM
6. CHECK WIRE HARNESS (CENTER CLUSTER INTEGRATION SWITCH OR NETWORK GATEWAY ECU) Check whether the output of the DTC stops when the integration switch, gateway ECU and the ECM connectors are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the integration switch or gateway ECU and the ECM is malfunctioning. NG: Go to step 7 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (CENTER CLUSTER INTEGRATION SWITCH OR NETWORK GATEWAY ECU)
7. CHECK DTC (TRANSPONDER KEY ECU ASSEMBLY) Check whether the output of the DTC stops when the transponder key ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the transponder key ECU is malfunctioning. NG: Go to step 8 OK: REPLACE TRANSPONDER KEY ECU ASSEMBLY
8. CHECK WIRE HARNESS (ECM - TRANSPONDER KEY ECU ASSEMBLY) Check whether the output of the DTC stops when the ECM and the transponder key ECU connector are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the ECM and the transponder key ECU is malfunctioning. NG: Go to step 9 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (ECM - TRANSPONDER KEY ECU ASSEMBLY)
9. CHECK DTC (MULTIPLEX TILT & TELESCOPIC ECU) (W/ TILT & TELESCOPIC) Check whether the output of the DTC stops when the tilt & telescopic ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the tilt & telescopic ECU is malfunctioning. NG: Go to step 10 OK: REPLACE MULTIPLEX TILT & TELESCOPIC ECU
10. CHECK WIRE HARNESS (TRANSPONDER KEY ECU ASSEMBLY - TILT & TELESCOPIC ECU) Check whether the output of the DTC stops when the transponder key ECU and the tilt & telescopic ECU connector are disconnected. (w/ Tilt & Telescopic) Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the transponder key ECU and the tilt & telescopic ECU is malfunctioning. NG: Go to step 11 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - TILT & TELESCOPIC ECU)
11. CHECK DTC (A/C AMPLIFIER) Check whether the output of the DTC stops when the A/ C amplifier connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the A/C amplifier is malfunctioning. NG: Go to step 12 OK: REPLACE AIR CONDITIONER AMPLIFIER ASSEMBLY
12. CHECK WIRE HARNESS (TILT & TELESCOPIC ECU - A/C AMPLIFIER) (W/ TILT & TELESCOPIC) Check whether the output of the DTC stops when the tilt & telescopic ECU and the A/C amplifier connector are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the tilt & telescopic ECU and the A/C amplifier is malfunctioning. NG: Go to step 13 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (TILT & TELESCOPIC ECU - A/C AMPLIFIER)
13. CHECK WIRE HARNESS (TRANSPONDER KEY ECU ASSEMBLY - A/C AMPLIFIER) Check whether the output of the DTC stops when the transponder key ECU and the A/C amplifier connector are disconnected. (w/o Tilt & Telescopic) Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the transponder key ECU and the A/C amplifier is malfunctioning. NG: REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - A/ C AMPLIFIER)
14. CHECK DTC (OUTER MIRROR CONTROL ECU ASSEMBLY (DRIVER SIDE)) Check whether the output of the DTC stops when the driver side outer mirror control ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the outer mirror control ECU is malfunctioning. NG: Go to step 15 OK: REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY
15. CHECK DTC (OUTER MIRROR CONTROL ECU ASSEMBLY (PASSENGER SIDE)) Check whether the output of the DTC stops when the passenger side outer mirror control ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the side outer mirror control ECU is malfunctioning. NG: Go to step 16 OK: REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY
16. CHECK DTC (WINDSHIELD WIPER RELAY ASSEMBLY) Check whether the output of the DTC stops when the wiper relay connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wiper ECU is malfunctioning. NG: Go to step 17 OK: REPLACE WINDSHIELD WIPER RELAY ASSEMBLY
17. CHECK DTC (POSITION CONTROL ECU & SWITCH ASSEMBLY) Check whether the output of the DTC stops when the power seat ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the power seat ECU is malfunctioning. NG: Go to step 18 OK: REPLACE POSITION CONTROL ECU & SWITCH ASSEMBLY
18. CHECK DTC (MULTIPLEX NETWORK DOOR ECU BACK) Check whether the output of the DTC stops when the door ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the door ECU is malfunctioning. NG: Go to step 19 OK: REPLACE MULTIPLEX NETWORK DOOR ECU BACK
19. CHECK DTC (HEADLIGHT SWIVEL ECU ASSEMBLY) Check whether the output of the DTC stops when the swivel ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the swivel ECU is malfunctioning. NG: Go to step 20 OK: REPLACE HEADLIGHT SWIVEL ECU ASSEMBLY
20. CHECK DTC (POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY) Check whether the output of the DTC stops when the master switch connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the master switch is malfunctioning. NG: Go to step 21 OK: REPLACE POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY
21. CHECK WIRE HARNESS (A/C AMPLIFIER ASSEMBLY - J/B NO. 3) Check whether the output of the DTC stops when the A/C amplifier and the 3G J/B connectors are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between A/C amplifier and the 3G J/B connector is malfunctioning. NG: Go to step 22 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (A/C AMPLIFIER - J/B NO. 3)
22. CHECK WIRE HARNESS (OUTER MIRROR CONTROL ECU (DRIVER SIDE) - J/B NO. 3) Check whether the output of the DTC stops when the 3K J/B connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the outer mirror ECU and the 3K J/B connector is malfunctioning. NG: Go to step 23 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (OUTER MIRROR CONTROL ECU - J/B NO.3)
23. CHECK WIRE HARNESS (OUTER MIRROR CONTROL ECU (PASSENGER SIDE) - J/B NO. 3) Check whether the output of the DTC stops when the 3B J/B connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the outer mirror ECU and the 3B J/B connector is malfunctioning. NG: Go to step 24 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (OUTER MIRROR CONTROL ECU - J/B NO. 3)
24. CHECK WIRE HARNESS (WINDSHIELD WIPER RELAY ASSEMBLY - J/B NO. 3) Check whether the output of the DTC stops when the 3C J/B connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the wiper relay and the 3C J/B connector is malfunctioning. NG: Go to step 25 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY -J/B NO. 3)
25. CHECK WIRE HARNESS (POSITION CONTROL ECU & SWITCH ASSEMBLY - J/B NO. 3) Check whether the output of the DTC stops when the 3J J/B connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the position control ECU & switch and the 3J J/B connector is malfunctioning. NG: Go to step 26 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (POSITION CONTROL ECU & SWITCH - J/B NO. 3)
26. CHECK WIRE HARNESS (MULTIPLEX NETWORK DOOR ECU BACK - J/B NO. 3) Check whether the output of the DTC stops when the 3J J/B connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the door ECU and the 3J J/B connector is malfunctioning. NG: Go to step 27 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (MULTIPLEX NETWORK DOOR ECU BACK -J/B NO. 3)
27. CHECK WIRE HARNESS (HEADLIGHT SWIVEL ECU ASSEMBLY - J/B NO. 3) Check whether the output of the DTC stops when the 3L J/B connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the ECU and the 3L J/B connector is malfunctioning. NG: Go to step 28 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (HEADLIGHT SWIVEL ECU ASSEMBLY - J/B NO. 3)
28. CHECK WIRE HARNESS (A/C AMPLIFIER - POWER WINDOW REGULATOR MASTER SWITCH) Check whether the output of the DTC stops when the A/C amplifier and the power window regulator master switch connectors are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the A/C amplifier and the power window regulator master switch is malfunctioning. NG: Go to step 29 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (A/C AMPLIFIER - POWER WINDOW REGULATOR MASTER SWITCH)
29. CHECK DTC (COMBINATION METER ASSEMBLY) Check whether the output of the DTC stops when the combination meter connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the combination meter is malfunctioning. NG: Go to step 30 OK: REPLACE COMBINATION METER ASSEMBLY
30. CHECK WIRE HARNESS (POWER WINDOW REGULATOR MASTER SWITCH - COMBINATION METER) Check whether the output of the DTC stops when the master switch and the combination meter connectors are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the master switch and the combination meter is malfunctioning. NG: Go to step 31 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY - COMBINATION)
31. CHECK DTC (AIRBAG SENSOR ASSEMBLY CENTER) Check whether the output of the DTC stops when the airbag sensor connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the airbag sensor is malfunctioning. NG: Go to step 32 OK: REPLACE AIR BAG SENSOR ASSEMBLY CENTER
32. CHECK WIRE HARNESS (COMBINATION METER ASSEMBLY - AIRBAG SENSOR ASSEMBLY CENTER) Check whether the output of the DTC stops when the combination meter and the airbag sensor connectors are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the combination meter and the airbag sensor is malfunctioning. NG: Go to step 33 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - AIRBAG SENSOR ASSEMBLY CENTER)
33. CHECK WIRE HARNESS (AIRBAG SENSOR ASSEMBLY CENTER - INSTRUMENT PANEL J/B) Check whether the output of the DTC stops when the airbag sensor and the instrument panel 1E J/B connectors are disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the airbag sensor and the instrument panel 1E J/B connector is malfunctioning. NG: Go to step 34 OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (AIRBAG SENSOR ASSEMBLY CENTER - INSTRUMENT PANEL J/B)
34. CHECK DTC (SLIDING ROOF DRIVE GEAR) Check whether the output of the DTC stops when the sliding roof ECU connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the drive gear is malfunctioning. NG: Go to step 35 OK: REPLACE SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY (SLIDING ROOF DRIVE GEAR)
35. CHECK DTC (RAIN SENSOR) Check whether the output of the DTC stops when the rain sensor connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the rain sensor is malfunctioning. NG: Go to step 36 OK: REPLACE RAIN SENSOR
36. CHECK WIRE HARNESS (INSTRUMENT PANEL J/B - SLIDING ROOF DRIVE GEAR & RAIN SENSOR) Check whether the output of the DTC stops when the instrument panel 1R J/B connector is disconnected. Standard: Neither DTC B1214 or B1215 is output. HINT: When the output of the DTC stops, the wire harness between the 1R instrument panel J/B connector and the drive gear or 1R instrument panel J/B connector and the rain sensor is malfunctioning. NG :REPAIR OR REPLACE HARNESS AND CONNECTOR (INSTRUMENT PANEL J/B - SLIDING ROOF DRIVE GEAR AND RAIN SENS) OK: REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

DTC B1245 is output when communication between the windshield wiper relay (ECU) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the wiper control switch can operate the wiper normally. NG: GO TO «WIPER AND WASHER SYSTEM»(ref-236012-S37651780042006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the A28 wiper relay connector. Disconnect the 3C J/B connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition A28-1 (MPX1) - 3C-9 (MPX1) Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK J/B NO. 3 Disconnect the 3C J/B connector. Disconnect the 3G J/B connector. Check the resistance between the J/B side connectors. TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition 3C-9 - 3G-2 Below 1 ohms NG: REPLACE J/B NO. 3 OK: REPLACE WINDSHIELD WIPER RELAY ASSEMBLY

DTC B1261 is output when communication between the ECM and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Turn the ignition ON and check that the engine starts. NG: GO TO «SFI SYSTEM»(/lexus/rx/ii-facelift-2006-2009/remont/removal-installation/#engine-control-system-3mz-fe) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the E6 ECM connector. Disconnect the T9 transponder key ECU connector. Disconnect the C4 integration switch connector (w/o LEXUS Navigation System). Disconnect the G3 gateway ECU connector (w/LEXUS Navigation System). Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition E6-18 (MPX1) - T9-5 (MPX2) Below 1 ohms E6-29 (MPX2) - C4-12 (MPX-) E6-29 (MPX2) - G3-11 (MPD2) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE ECM

DTC B1262 is output when communication between the A/C amplifier (ECU) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the A/C switch can operate the air conditioner normally. NG: GO TO «AIR CONDITIONING SYSTEM»(ref-236010-S30921850592006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the A8 A/C amplifier ECU connector. Disconnect the P22 switch connector. Disconnect the T4 tilt & telescopic ECU connector. Disconnect the T9 transponder key ECU connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition A8-3 (MPX+) - P22-7 (MPX1) Below 1 ohms A8-4 (MPX-) - T4-5 (MPX1) A8-4 (MPX-) - T9-4 (MPX1) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE A/C AMPLIFIER ASSEMBLY

DTC B1271 is output when communication between the combination meter and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the tachometer can operate properly while the engine is idling. NG: GO TO «COMBINATION METER»(ref-236027-S07965956162006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the C8 meter connector. Disconnect the C9 meter connector. Disconnect the A20 airbag sensor connector. Disconnect the P22 master switch connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition C8-5 (MPX+) - A20-22 (MPX2) Below 1 ohms C9-4 (MPX-) - P22-8 (MPX2) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE COMBINATION METER ASSEMBLY

DTC B1272 is output when communication between the position control ECU & switch (power seat ECU) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the manual switch of the front power seat can move the driver side seat normally. NG: GO TO «FRONT POWER SEAT CONTROL SYSTEM (W/ MEMORY)»(ref-236017-S27023792592006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the P32 ECU & switch connector. Disconnect the 3J J/B No. 3 connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition P32-1 (MPX1) - 3J-5 (MPX1) Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK J/B NO. 3 Disconnect the 3G J/B connector. Disconnect the 3J J/B connector. Check the resistance between the J/B side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition 3G-2 - 3J-5 Below 1 ohms NG: REPLACE J/B NO. 3 OK: REPLACE POSITION CONTROL ECU & SWITCH ASSEMBLY

DTC B1273 is output when communication between the sliding roof drive gear (sliding roof ECU) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. INSPECT APPARATUS Choose the apparatus to be inspected. TESTER CONNECTION SPECIFIED CONDITION CHART A MULTI-PANEL MOON ROOF TYPE B STANDARD MOON ROOF TYPE B: Go to step 4 A: Go to next step
2. CHECK OPERATION Check that the sliding roof system operates normally. NG: GO TO «SLIDING ROOF SYSTEM»(ref-236021-S03716682402006062900000) OK: Go to next step
3. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the M12 gear connector. Disconnect the 1R J/B connector. Check the resistance between the wire harness side connectors. TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition M12-5 (MPX1) - 1R-9 (MPX1) Below 1 ohms Resistance NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY
4. CHECK OPERATION Check that the tilt or slide switch can operate the sliding roof normally. NG: GO TO «SLIDING ROOF SYSTEM»(ref-236021-S03716682402006062900000) OK: Go to next step
5. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the M12 gear connector. Disconnect the 1R J/B connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition M12-10 (MPX1) - 1R-9 (MPX1) Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY

DTC B1277 is output when communication between the integration switch and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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Scheme 72

1. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the C4 switch connector. Disconnect the B5 ECU connector. Disconnect the E6 ECM connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition C4-5 (MPX+) - B5-21 (MPX2) Below 1 ohms C4-12 (MPX-) - E6-29 (MPX2) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK CENTER CLUSTER INTEGRATION SWITCH ASSEMBLY (POWER SOURCE) Disconnect the C4 switch connector. Check the voltage between the wire harness side connector and the body ground. Voltage TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition C4-1 (+B) - Body ground 10 to 14 V NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK CENTER CLUSTER INTEGRATION SWITCH ASSEMBLY (GROUND) Disconnect the C4 switch connector. Check the resistance between the wire harness side connector and the body ground. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition C4-7 (GND) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE CENTER CLUSTER INTEGRATION SWITCH ASSEMBLY

DTC B1279 is output when communication between the rain sensor and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the R7 sensor connector. Disconnect the 1R J/B connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition R7-2 (MPX) - 1R-9 (MPX1) Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK RAIN SENSOR (POWER SOURCE) Disconnect the R7 sensor connector. Check the voltage between the wire harness side connector and the body ground. Voltage TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Switch Position Specified Condition R7-1 (SIG) - Body ground Ignition switch ON 10 to 14 V NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK RAIN SENSOR (GROUND) Disconnect the R7 sensor connector. Check the resistance between the wire harness side connector and the body ground. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition R7-3 (ES) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE RAIN SENSOR

DTC B1281 is output when communication between the airbag sensor (ECU) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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Scheme 78

1. CHECK OPERATION Start the engine and check that the SRS warning light on the combination meter goes off. NG: GO TO «SUPPLEMENTAL RESTRAINT SYSTEM»(/lexus/rx/ii-facelift-2006-2009/remont/airbag/#supplemental-restraint-system) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the A20 sensor connector. Disconnect the C8 meter connector. Disconnect the 1E J/B connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition A20-24 (MPX1) - 1E-7 (MPX1) Below 1 ohms A20-22 (MPX2) - C8-5 (MPX1) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE AIR BAG SENSOR ASSEMBLY CENTER

DTC B1287 is output when communication between the multiplex network door ECU back (back door ECU) and the body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Check that the power back door switch can operate the back door normally. NG: GO TO «POWER BACK DOOR SYSTEM»(ref-236020-S14185932872006062900000) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the P13 ECU connector. Disconnect the 3J J/B connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition P13-22 (MPX1) - 3J-5 (MPX1) Below 1 ohms NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK J/B NO. 3 Disconnect the 3G J/B connector. Disconnect the 3J J/B connector. Check the resistance between the J/B side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition 3G-2 - 3J-5 Below 1 ohms NG: REPLACE J/B NO. 3 OK: REPLACE MULTIPLEX NETWORK DOOR ECU BACK

DTC B1293 is output when communication between the network gateway ECU and the body ECU stops. for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the G3 gateway ECU connector. Disconnect the B5 body ECU connector. Disconnect the E6 ECM connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition G3-4 (MPD1) - B5-21 (MPX2) Below 1 ohms G3-11 (MPD2) - E6-29 (MPX2) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK NETWORK GATEWAY ECU (POWER SOURCE) Disconnect the G3 ECU connector. Check the voltage between the wire harness side connector and the body ground. Voltage TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition G3-8 (BATT) - Body ground 10 to 14 V NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK NETWORK GATEWAY ECU (GROUND) Disconnect the G3 ECU connector. Check the resistance between the wire harness side connector and the body ground. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition G3-7 (CG) - Body ground Below 1 ohms G3-14 (GND) - Body ground NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE NETWORK GATEWAY ECU

DTC B1294 is output when communication between the transponder key ECU (immobilizer ECU) and the. body ECU stops for more than 10 seconds.

DIAGNOSTIC TROUBLE CODE CHART

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1. CHECK OPERATION Turn the ignition switch ON and check that the engine starts. NG: GO TO «ENGINE IMMOBILIZER»(ref-236030) OK: Go to next step
2. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the T9 transponder key ECU connector. Disconnect the T4 tilt & telescopic ECU connector. Disconnect the A8 A/C amplifier connector. Disconnect the E6 ECM connector. Check the resistance between the wire harness side connectors. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition T9-4 (MPX1) - T4-14 (MPX2) Below 1 ohms T9-4 (MPX1) - A8-4 (MPX-) T9-5 (MPX2) - E6-18 (MPX1) NG: REPAIR OR REPLACE HARNESS AND CONNECTOR OK: REPLACE TRANSPONDER KEY ECU ASSEMBLY

See also:
• SFI SYSTEM
• SUPPLEMENTAL RESTRAINT SYSTEM