Multiplex Communication

MULTIPLEX COMMUNICATION MULTIPLEX COMMUNICATION SYSTEM
MP1
MULTIPLEX COMMUNICATION SYSTEM

PRECAUTION
1. DISCONNECT AND RECONNECT CABLE OF NEGATIVE BATTERY TERMINAL NOTICE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected.
See procedure See page ME-10
System Name METER / GAUGE SYSTEM
Cable
(a) Before performing electronic work, disconnect the cable from the negative (-) battery terminal in order to prevent it from shorting and burning out. (b) Before disconnecting and reconnecting the battery cable, turn the ignition switch OFF and the headlight dimmer switch OFF. Then loosen the terminal nut completely. Do not damage the cable or terminal. (c) When the battery cable is disconnected, the clock and radio settings and stored DTCs are erased. Therefore, before disconnecting the battery cable, make a notes of them.
Negative (-) Battery Terminal

D033496E01
MP
MP2
PARTS LOCATION
Back Door ECU
Main Body ECU (Driver Side J/B)
MP
B137551E01
MP3
SYSTEM DIAGRAM
Main Body ECU Back Door ECU
BECU ECU-B POWER BDR J/B Short Pin ALT GND MPX2 MPX2
Battery
B137552E01
MP
MP4
SYSTEM DESCRIPTION
1. MULTIPLEX COMMUNICATION SYSTEM (BEAN) (a) The BEAN communication line consists of 2 systems: One is a system with a loop-shaped line that links the back door ECU with the main body ECU, which is located in the center of the line. Since the line for the back door ECU is loopshaped, communication can be maintained by the line that is not open even if part of the line becomes open for some reason. In the case that there is a short-circuit (bus-down) in the line, however, all the BEAN communication becomes impossible in the system and some DTCs are output. HINT: When bus-down occurs, communication from the related ECU stops. Therefore, DTCs cannot be output, so perform a DTC (SAE code) inspection using the intelligent tester. The back door ECU has a single communication line. Therefore, if the line has a short-circuit (busdown), the BEAN communication will be impossible and DTCs will not be output, either. CHECK COMMUNICATION FUNCTION (a) Check the battery voltage. Standard voltage: 11 to 14 V (b) Inspect the DTC output. (1) Check for DTCs concerning the main body ECU by connecting the intelligent tester to the DLC3 and turning the ignition switch ON. (2) When the display shows DTCs concerning the ECU being unconnected and the communication bus defective, perform the inspection depending on the troubleshooting procedures. HINT: When other DTCs are output, refer to the DTC table and check the applicable section.
2.
MP
MP5
HOW TO PROCEED WITH TROUBLESHOOTING

HINT: Use this procedure to troubleshoot the multiplex communication system. The intelligent tester should be used in step 2.
1
NEXT
VEHICLE BROUGHT TO WORKSHOP
CHECK FOR DTC (a) Check for DTCs and note any codes that are output. (b) Delete the DTC. (c) Recheck for DTCs. Try to prompt the DTC by simulating the original activity that the DTC suggests. Result
Result DTC does not recur DTC recurs Proceed to A B
B A
GO TO DTC CHART
OVERALL ANALYSIS AND TROUBLESHOOTING (a) Terminals of ECU (See page MP-6).
NEXT
4
NEXT
ADJUST, REPAIR OR REPLACE
5
NEXT END
CONFIRMATION TEST
MP
MP6
TERMINALS OF ECU
1. CHECK MAIN BODY ECU (a) Disconnect the 1B, 1E, 1F, 1L and E6 main body ECU connectors.
Main Body ECU: Left View:

18 19 20 21
E8
22 23 24 25 26
E7
17 18 19 20 21 22 23 24 23 24 25 26
E6
27 28 29 30
7 8 9 10 11 12 13 14 15 16 17 1 2 3 4 5 6
7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6
11 12 13 14 15 16 17 18 19 20 21 22 1 2 3 4 5 6 7 8 9 10
E8
E7
E6
Rear View: 1A
10 9 8 7 20 19 18 17 6 5 4 3 2 1 16 15 14 13 12 11
1B
5 4 3 2 1
1A
1B
13 12 11 10 9 8 7 6
1C 1C
1 2
1D 1D
2 6 5 4 1 3
1E 1F 1F
1E
MP
12 11 10 9 24 23 22 21
8 7 20 19
6 5 4 3 2 1 18 17 16 15 14 13
8 7 16 15
6 5 4 3 2 1 14 13 12 11 10 9
B136051E02
MP7
Main Body ECU:
Front View:
1H
1J
17 18 19 20 21 22 1 2 3 4 5 6 23 24 25 26 7 8 9 10 27 28 29 30 31 32 11 12 13 14 15 16
1G
4
2 1 4 3
3 2 1
1G 1H 1K 1J 1L
1K
1L
9 10 11 12 13 14 1 2 3 4 5 6
15 16 7 8
13 14 15 16 17 18 1 2 3 4 5 6
19 20 7 8
21 22 23 24 9 10 11 12
B136052E02
MP
MP8
(b) Measure the voltage of the wire harness side connectors. Standard voltage:
Symbols (Terminals No.) BECU (1B-4) - Body ground BECU (1L-4) - Body ground BECU (1F-12) - Body ground BDR1 (1E-9) - Body ground MPX2 (E6-23) - Body ground Wiring Color W-R - Body ground W-R - Body ground W-R - Body ground B-Y - Body ground BR-R - Body ground Terminal Description Power source (+B) Power source (+B) Power source (+B) Power source (+B) Multiplex communication signal Condition Always Always Always Always During communication Specified Condition 11 to 14 V 11 to 14 V 11 to 14 V 11 to 14 V Signal waveform
2.
If the result is not as specified, there may be a malfunction on the wire harness side. CHECK BACK DOOR ECU (a) Disconnect the S2 ECU connector.
S2
S5
B062706E01
(b) Measure the voltage of the wire harness side connector. Standard voltage:
Symbols (Terminals No.) GND (S2-3) - Body ground BECU (S2-5) - GND (S23) BDR (S2-4) - GND (S2-3) MPX2 (S2-1) - Body ground SIG (S2-6) - Body ground Wiring Color W-B - Body ground W-R - W-B L-O - W-B BR-R - Body ground B-R - Body ground Terminal Description Ground for main power supply Power source (+B) Power source (+B) Multiplex communication signal Power source (IG) Condition Ground for main power supply Always Always During communication Ignition switch ON Specified Condition Below 1 V 11 to 14 V 11 to 14 V Signal waveform 11 to 14 V
If the result is not as specified, there may be a malfunction on the wire harness side.
MP
MP9
DIAGNOSIS SYSTEM
1. DESCRIPTION (a) The main body 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. CHECK DLC3 (a) The ECU uses ISO 15765-4 for communication. The terminal arrangement of the DLC3 complies with ISO 15031-3 and matches the ISO 15765-4 format.
2.
CG SG CANH SIL
CANL
BAT
H100769E16
Symbols (Terminal No.) SIL (7) - SG (5) CG (4) - Body ground SG (5) - Body ground BAT (16) - Body ground CANH (6) - CANL (14) CANH (6) - CG (4) CANL (14) - CG (4) CANH (6) - BAT (16) CANL (14) - BAT (16)
Terminal Description Bus "+" line Chassis ground Signal ground Battery positive HIGH-level CAN bus line HIGH-level CAN bus line LOW-level CAN bus line HIGH-level CAN bus line LOW-level CAN bus line
Condition During transmission Always Always Always Ignition switch OFF* Ignition switch OFF* Ignition switch OFF* Ignition switch OFF* Ignition switch OFF*
Specified Condition Pulse generation Below 1 Below 1 11 to 14 V 54 to 69 200 or more 200 or more 6 k or more 6 k or more
CAUTION: *: Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors. If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.
Intelligent Tester
CAN VIM DLC3

H102157E03
(b) Intelligent tester HINT: Connect the cable of the intelligent tester to the CAN VIM, connect the CAN VIM to the DLC3, turn the ignition switch ON 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.
MP
MP10
3.
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. INSPECT BATTERY VOLTAGE Standard voltage: 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding. CHECK DTC (a) Connect the intelligent tester to the DLC3. (b) Turn the ignition switch ON. (c) Enter the following menus: DIAGNOSIS/OBD/ MOBD/BODY/DTC INFO. (d) Check the DTCs on the tester screen. HINT: Refer to the intelligent tester operator's manual for further details. CLEAR DTC (a) Connect the intelligent tester to the DLC3. (b) Turn the ignition switch ON. (c) Erase the DTCs by following the prompts on the tester screen. (d) Enter the following menus: DIAGNOSIS/OBD/ MOBD/BODY/DTC INFO. HINT: Refer to the intelligent tester operator's manual for further details.
Intelligent Tester
DTC CHECK / CLEAR

1.
CAN VIM DLC3

H102157E03
2.
MP
MP11
DIAGNOSTIC TROUBLE CODE CHART

HINT: If a malfunction code is displayed during the DTC check, check the circuit corresponding to the code in the table below. Proceed to the page given for the circuit. MULTIPLEX COMMUNICATION SYSTEM
DTC No. B1214 Detection Item Short to B+ in Door System Communication Bus Malfunction Short to GND in Door System Communication Bus Malfunction Back Door ECU Communication Stop Trouble area 1. Back door ECU 2. Main Body ECU 3. Wire Harness 1. Back door ECU 2. Main Body ECU 3. Wire Harness 1. Back door ECU 2. Wire Harness See page MP-11
B1215
MP-11
B1287
MP-14
MP
MP12
DTC DTC
DESCRIPTION
B1214 B1215
Short to B+ in Door System Communication Bus Malfunction Short to GND in Door System Communication Bus Malfunction
When a +B short circuit or body ground short circuit is detected on the communication bus (BEAN), BEAN is disabled and a DTC is output.
DTC No. B1214 DTC Detection Condition Communication circuit and +B battery system short Back door ECU Main body ECU Wire harness Back door ECU Main body ECU Wire harness Trouble Area
B1215
Door system communication circuit and body ground short
WIRING DIAGRAM
Main Body ECU
Back Door ECU
MPX2
MPX2
B137556E01
INSPECTION PROCEDURE
CHECK DIAGNOSTIC TROUBLE CODE (BACK DOOR ECU) (a) Disconnect the back door ECU connector and check for DTCs B1214 and B1215.
MP
MP13
Main Body ECU
Back Door ECU
MPX2
MPX2
B137555E01
OK: Neither DTC B1214 nor DTC B1215 is output. NOTICE: Disconnect the connector in the operational sequence, and start the next step after the connector is reconnected. OK NG REPLACE BACK DOOR ECU
CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BACK DOOR ECU) (a) Check for a short-circuit in B+ or body ground.
Main Body ECU Back Door ECU
MPX2
MPX2
B137554E01
MP
MP14
Wire Harness Side:
Main Body ECU E6
(b) Disconnect the S2 back door ECU connector and E6 main body ECU connector. (1) Measure the voltage between the terminals of the S2 back door ECU or E6 main body ECU connector and body ground.
1 2 3 4 5 6 7 8 9
10
11 12 13 14 15 16 17 18 19 20 21 22
MPX2
23 24 25 26
27 28 29 30
Front View
Back Door ECU S2 MPX2

1 2 3 4 5 6 7 8
Front View
B137571E03
Standard voltage
Tester Connection E6-23 (MPX2) or S2-1 (MPX2) - Body ground Condition Ignition switch ON Specified Condition Below 1 V
(2) Check the resistance. Standard resistance

Tester Connection E6-23 (MPX2) or S2-1 (MPX2) - Body ground Specified Condition 10 k or higher
(c) Reconnect the back door ECU connector and main body ECU connector. NG REPAIR OR REPLACE WIRE HARNESS BETWEEN MAIN BODY ECU AND BACK DOOR ECU
OK REPLACE MAIN BODY ECU
MP
MP15
DTC
DESCRIPTION
B1287
Back Door ECU Communication Stop
DTC B1287 is output when communication between the back door ECU and the main body ECU stops for more than 10 seconds.
DTC No. B1287 DTC Detection Condition Back door ECU communication stops Back door ECU Wire harness Trouble Area
WIRING DIAGRAM
Back Door ECU
Main Body ECU
BECU ECU-B POWER BDR J/B Short Pin ALT GND MPX2 MPX2
Battery
B137552E01
MP
MP16
INSPECTION PROCEDURE
CHECK COMMUNICATION LINE (a) Disconnect the E6 main body ECU and S2 back door ECU connectors. (b) Check the resistance. Standard resistance
Tester Connection Specified Condition Below 1 E6-23 (MPX2) - S2-1 (MPX2)
Wire Harness Side:
Main Body ECU E6
(c) Reconnect the main body ECU and back door ECU connectors.
1 2 3 4 5 6 7 8 9 11 12 13 14 15 16 17 18 19 20 21 22 10
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
MPX2
23 24 25 26
27 28 29 30
Front View
Back Door ECU S2 MPX2

1 2 3 4 5 6 7 8
Front View
B137571E03
OK
CHECK BACK DOOR ECU (POWER SOURCE) (a) Disconnect the S2 back door ECU connector. (b) Measure the voltage between the terminals of the S2 back door ECU connector and body ground. Standard voltage
Tester Connection S2-5 (BECU) - Body ground Specified Condition 11 to 14 V
Wire Harness Side:
Back Door ECU
(c) Reconnect the ECU connector.

S2
NG
MP
1 2 3 4 5 6 7 8
BECU Front View

B137572E01
MP17
OK
CHECK BACK DOOR ECU (GROUND) (a) Disconnect the S2 back door ECU connector. (b) Check the resistance. Standard resistance
Tester Connection Specified Condition Below 1 S2-3 (GND) - Body ground
Wire Harness Side:
Back Door ECU
(c) Reconnect the ECU connector.

S2
1 2 3 4 5 6 7 8
NG
GND
Front View
B137572E05
OK REPLACE BACK DOOR ECU
MP

Multiplex Communication

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MULTIPLEX COMMUNICATION MULTIPLEX COMMUNICATION SYSTEM