Multiplex Communication System (Diagnostics - Introduction): Diagnosis Lexus IS II facelift 2

HOW TO PROCEED WITH TROUBLESHOOTING [08/2012 - ]

HINT

1. Use this procedure to troubleshoot the multiplex communication system.
2. Techstream should be used in step 2.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. CHECK FOR DTC Check for DTCs and note any codes that are output. Delete the DTC. Recheck for DTCs. Try to prompt the DTC by simulating the original activity that the DTC suggests. Result Result Proceed to DTC does not reoccur A DTC reoccurs B B --> GO TO DTC CHART A: Go to next step
3. OVERALL ANALYSIS AND TROUBLESHOOTING Terminals of ECU. Refer to «TERMINALS OF ECU [08/2012 - ]»(ref-606519-S35206108462014032500000) . NEXT: Go to next step
4. ADJUST, REPAIR OR REPLACE NEXT: Go to next step
5. CONFIRMATION TEST NEXT --> END

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Scheme 21

1. CHECK MULTIPLEX NETWORK GATEWAY ECU Disconnect the multiplex network gateway ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition IG (J76-1) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V IG (J76-1) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V ACC (J76-2) - Body ground BE - Body ground Power source (ACC) Engine switch: off Below 1 V ACC (J76-2) - Body ground BE - Body ground Power source (ACC) Engine switch: on (IG) 10 to 14 V BATT (J76-10) - Body ground LG - Body ground Power source (+B) Always 10 to 14 V MPI1 (J76-4) - Body ground BR - Body ground MPX line Always 10 kohms or higher MPI2 (J76-13) - Body ground BR - Body ground MPX line Always 10 kohms or higher MPD1 (J76-3) - Body ground GR - Body ground MPX line Always 10 kohms or higher MPD2 (J76-12) - Body ground GR - Body ground MPX line Always 10 kohms or higher GND (J76-24) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms If the result is not as specified, there may be a malfunction on the wire harness side.
2. CHECK MAIN BODY ECU LH Disconnect the main body ECU LH connectors. Measure the voltage and resistance of the wire harness side connectors. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (LK-6) - Body ground Y - Body ground Power source (IG) Engine switch: off Below 1 V IG (LK-6) - Body ground Y - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V BKUP (LJ-23) - Body ground Y - Body ground Power source (+B) Always 10 to 14 V MPXB (LD-18) - Body ground LG - Body ground Power source (+B) Always 10 to 14 V GND (LD-3) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms SGND (LD-8) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms SGND (LD-9) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (Q3-15) - Body ground GR - Body ground MPX line Always 10 kohms or higher MPX2 (A30-17) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
3. CHECK MAIN BODY ECU RH Disconnect the main body ECU RH connectors. Measure the voltage and resistance of the wire harness side connectors. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (RM-1) - Body ground B-W - Body ground Power source (IG) Engine switch: off Below 1 V IG (RM-1) - Body ground B-W - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V ACC (RD-27) - Body ground BE - Body ground Power source (ACC) Engine switch: off Below 1 V ACC (RD-27) - Body ground BE - Body ground Power source (ACC) Engine switch: on (ACC) 10 to 14 V ALTB (RA-15) - Body ground SB - Body ground Power source (+B) Always 10 to 14 V BECU (RK-5) - Body ground G-R - Body ground Power source (+B) Always 10 to 14 V BATB (RN-1) - Body ground R - Body ground Power source (+B) Always 10 to 14 V GND2 (RD-11) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms GND2 (RD-7) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms GND2 (RA-4) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms GND2 (RA-5) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms GND1 (RD-17) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (RA-20) - Body ground GR - Body ground MPX line Always 10 kohms or higher MPX1 (RJ-21) - Body ground GR - Body ground MPX line Always 10 kohms or higher MPX2 (J75-21) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
4. CHECK TILT AND TELESCOPIC ECU Disconnect the tilt and telescopic ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (J28-8) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V IG (J28-8) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V ECUB (J28-9) - Body ground LG - Body ground Power source (+B) Always 10 to 14 V +B (J28-2) - Body ground SB - Body ground Power source (+B) Always 10 to 14 V GND (J28-11) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (J28-5) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
5. CHECK POWER WINDOW MASTER SWITCH ECU Disconnect the power window master switch ECU connector. Measure the voltage and the resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition SIG (M17-18) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V SIG (M17-18) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V CPUB (M17-15) - Body ground G - Body ground Power source (+B) Always 10 to 14 V E (M17-12) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (M17-3) - Body ground GR - Body ground MPX line Always 10 kohms or higher MPX2 (M17-2) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
6. CHECK OUTER MIRROR CONTROL ECU LH Disconnect the outer mirror control ECU LH connector. Measure the voltage and the resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition SIG (M10-3) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V SIG (M10-3) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V CPUB (M10-4) - Body ground G - Body ground Power source (+B) Always 10 to 14 V BDR (M10-6) - Body ground L - Body ground Power source (+B) Always 10 to 14 V GND (M10-1) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (M10-8) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
7. CHECK CERTIFICATION ECU Disconnect the certification ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (P33-18) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V IG (P33-18) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V ACC (P33-19) - Body ground BE - Body ground Power source (ACC) Engine switch: off Below 1 V ACC (P33-19) - Body ground BE - Body ground Power source (ACC) Engine switch: on (IG) 10 to 14 V +B1 (P33-1) - Body ground L - Body ground Power source (+B) Always 10 to 14 V E (P33-17) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (P33-27) - Body ground GR - Body ground MPX line Always 10 kohms or higher MPX2 (P33-28) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
8. CHECK FRONT CONTROLLER ECU Disconnect the front controller ECU connectors. Measure the voltage and resistance of the wire harness side connectors. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition 2E-3 - Body ground B-Y - Body ground Power source (IG) Engine switch: off Below 1 V 2E-3 - Body ground B-Y - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V 2E-4 - Body ground G-R - Body ground Power source (+B) Always 10 to 14 V 2F-1 - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms 2F-6 - Body ground GR - Body ground MPX line Always 10 kohms or higher 2F-5 - Body ground L - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
9. CHECK OUTER MIRROR CONTROL ECU RH Disconnect the outer mirror control ECU RH connector. Measure the voltage and the resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition SIG (L10-3) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V SIG (L10-3) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V CPUB (L10-4) - Body ground G - Body ground Power source (+B) Always 10 to 14 V BDR (L10-6) - Body ground L - Body ground Power source (+B) Always 10 to 14 V GND (L10-1) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (L10-8) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
10. CHECK POWER SEAT CONTROL ECU LH Disconnect the power seat control ECU LH connectors. Measure the voltage and resistance of the wire harness side connectors. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (U7-4) - Body ground Y - Body ground Power source (IG) Engine switch: off Below 1 V IG (U7-4) - Body ground Y - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V +B (U6-5) - Body ground L - Body ground Power source (+B) Always 10 to 14 V SYSB (U7-8) - Body ground LG - Body ground Power source (+B) Always 10 to 14 V GND (U6-1) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (U7-1) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
11. CHECK SLIDING ROOF CONTROL ECU Disconnect the sliding roof control ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (R6-6) - Body ground V - Body ground Power source (IG) Engine switch: off Below 1 V IG (R6-6) - Body ground V - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V B (R6-5) - Body ground L - Body ground Power source (+B) Always 10 to 14 V E (R6-7) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (R6-10) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
12. CHECK RAIN SENSOR Disconnect the rain sensor connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition SIG (R7-1) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V SIG (R7-1) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V MPX (R7-2) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
13. CHECK POWER SOURCE CONTROL ECU Disconnect the power source control ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition AM1 (J55-33) - Body ground BE - Body ground Power source (+B) Always 10 to 14 V AM2 (J55-12) - Body ground BE - Body ground Power source (+B) Always 10 to 14 V MPX1 (J55-7) - Body ground GR - Body ground MPX line Always 10 kohms or higher MPX2 (J55-24) - Body ground GR - Body ground MPX line Always 10 kohms or higher GND2 (J55-6) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms If the result is not as specified, there may be a malfunction on the wire harness side.
14. CHECK WINDSHIELD WIPER SWITCH ASSEMBLY Disconnect the windshield wiper switch assembly connector. Measure the resistance and voltage of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (J26-2) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V IG (J26-2) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V B (J26-1) - Body ground LG - Body ground Power source (+B) Always 10 to 14 V E (J26-5) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX1 (J26-6) - Body ground GR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
15. CHECK COMBINATION METER ECU Disconnect the combination meter ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG+ (J34-12) - Body ground BE - Body ground Power source (IG) Engine switch: off Below 1 V IG+ (J34-12) - Body ground BE - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V B (J34-23) - Body ground L - Body ground Power source (+B) Always 10 to 14 V B (J34-24) - Body ground LG - Body ground Power source (+B) Always 10 to 14 V E2 (J34-1) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms ES (J34-13) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms MPX+ (J34-6) - Body ground BR - Body ground MPX line Always 10 kohms or higher MPX- (J34-18) - Body ground BR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
16. CHECK CLEARANCE WARNING ECU Disconnect the clearance warning ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG (Q37-8) - Body ground Y - Body ground Power source (IG) Engine switch: off Below 1 V IG (Q37-8) - Body ground Y - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V E (Q37-27) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms M+ (Q37-26) - Body ground BR - Body ground MPX line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side.
17. CHECK AIR CONDITIONING ECU Disconnect the air conditioning ECU connector. Measure the voltage and the resistance of the wire harness side connector. Symbols (Terminals No.) Wiring Color Terminal Description Condition Specified Condition IG+ (J58-21) - Body ground B - Body ground Power source (IG) Engine switch: off Below 1 V IG+ (J58-21) - Body ground B - Body ground Power source (IG) Engine switch: on (IG) 10 to 14 V B (J58-1) - Body ground Y - Body ground Power source (+B) Always 10 to 14 V MPX+ (J58-30) - Body ground BR - Body ground MPX line Always 10 kohms or higher MPX- (J58-31) - Body ground BR - Body ground MPX line Always 10 kohms or higher GND (J58-20) - Body ground W-B - Body ground Ground for main power supply Always Below 1 ohms If the result is not as specified, there may be a malfunction on the wire harness side.

Scheme 22

1. DESCRIPTION The network gateway ECU controls the functions of the multiplex communication system on the vehicle. Data of the multiplex communication system and the Diagnostic Trouble Codes (DTC) can be read through the Data Link Connector 3 (DLC3) of the vehicle.
2. CHECK DLC3 The vehicle's ECU uses the ISO 15765-4 for communication protocol. The terminal arrangement of the DLC3 complies with SAEJ 1962 and matches the ISO 15765-4 format. Symbols (Terminal No.) Terminal Description Condition Specified Condition SIL (7) - SG (5) Bus "+" line During transmission Pulse generation CG (4) - Body ground Chassis ground Always Below 1 ohms SG (5) - Body ground Signal ground Always Below 1 ohms BAT (16) - Body ground Battery positive Always 11 to 14 V If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector. Techstream HINT: Connect the cable of Techstream to the DLC3, turn the engine switch on (IG) and attempt to use the tester. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the tester. If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle. If communication is still not possible when the tester is connected to another vehicle, the problem may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.
3. INSPECT BATTERY VOLTAGE Standard voltage 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding.

DTC CHECK / CLEAR [08/2012 - ]

1. CHECK DTC Connect Techstream to the DLC3. Turn the engine switch on (IG). Check the DTCs on the tester screen. HINT: Refer to Techstream operator's manual for further details.
2. CLEAR DTC Connect Techstream to the DLC3. Turn the engine switch on (IG). Erase the DTCs by following the prompts on the tester screen. HINT: Refer to Techstream operator's manual for further details.

DIAGNOSTIC TROUBLE CODE CHART [08/2012 - ]

If malfunction code is displayed during DTC check, check the circuit corresponding to the code in the table below. Proceed to the Service Information given for the circuit.

MULTIPLEX COMMUNICATION SYSTEM

When "+B or GND short malfunction of communication bus" DTCs (B1266 and B1267) are detected at the same time as "communication stop" DTCs (B1200, B1216, B1208, B1209, B1213, B1272, B1287 and B1294), please repair the "+B or GND short malfunction of communication bus" DTCs first.

When "+B or GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTCs (B1245, B1262, B1271, B1273, B1277, B1279 and B1281), please repair the "+B or GND short malfunction of communication bus" DTCs first.