Large-scale multiplex communication system for vehicle body [LIN]
Parts location System information Troubleshooting Diagnostic trouble codes
NETWORK / COMMUNICATION SYSTEM
LARGE-SCALE MULTIPLEX COMMUNICATION SYSTEM FOR VEHICLE BODY [LIN]
PARTS LOCATION
LIST OF DIAGNOSTIC CODES
DESCRIPTION OF FUNCTIONS
1. Function description of large-scale multiplex communication system for vehicle body [LIN]
(1) Large-scale multiplex communication system for vehicle body [LIN] is used for communication systems between body system components. When communication failure occurs due to an open circuit and other defects in communication line, diagnostic code of the corresponding system is output by the control master ECM. (Communication systems and the connected ECMs are described below).
NOTE:
Each ECM has the failsafe function to ensure the minimum performance and system protection in case of communication failure.
(a) Door system LIN communication system
| Parts (ECM name) |
Control master (LIN communication DTC output function) |
|---|---|
| Main body ECM (Multiplex network body computer) (Main body ECM) |
O (with output function) |
| Power window regulator master switch ASSY |
× (without output function) |
(b) Collation system LIN communication system (with smart entry)
*: with ID code box
| Parts (ECM name) |
Control master (LIN communication DTC output function) |
|---|---|
| Smart key computer ASSY (Collation ECM) |
O (with output function) |
| Steering lock actuator ASSY (Steering lock ECM) |
× (without output function) |
| ID code box * |
× (without output function) |
HOW TO TROUBLESHOOT
1.
Bringing in the car
Next▼
2.
Phenomenon check
Next▼
3.
Communication function inspection of the CAN communication system
(1) Check that there are no abnormal condition in CAN communication system. (Refer to 
)
)
Result
| Result |
Go to |
|---|---|
| If CAN communication system is normal [No DTC (CAN communication error, ECM communication error, or lost communication) is output] |
A |
| If CAN communication system is not normal [DTC (CAN communication error, ECM communication error, or lost communication) is output] |
B |
B
>Repair the fault according to the troubleshooting procedure for CAN system.
A▼
4.
Communication function check of the large-scale multiplex communication system for vehicle body [LIN]
(1) Use SSM3 to check the communication functions of the large-scale multiplex communication system for vehicle body [LIN] to confirm the communication system has no fault. (Refer to )
)
NOTE:
For details of DTC output, refer to the List of DTC. (Refer to )
)Result
| Result |
Go to |
|---|---|
| If the communication system is defective [DTC (LIN communication error, ECM communication error, or lost communication) is output] |
A |
| If DTC other than for communication system is output [No DTC (LIN communication error, ECM communication error, or lost communication) is output] |
B |
B
>Go to the corresponding section for DTC output
A▼
5.
DTC check
(1) Use SSM3 to check DTC and record the code output if any. (Refer to )
)(2) Clear diagnostic code. (Refer to )
)(3) Simulate the conditions indicated by DTC to check whether the same DTC recur.
Result
| Result |
Go to |
|---|---|
| If no DTC is output (phenomenon can be confirmed and reproducible) |
A |
| If no DTC is output (phenomenon can not be confirmed and not reproducible) |
B |
| If DTC is output |
C |
B
>Go to “How to simulate trouble phenomenon”. (Refer to )
)C
>Go to Troubleshooting flowchart of each DTC. (Refer to )
)A▼
6.
Troubleshoot the malfunction according to the method below
(1) ECM terminal arrangement (Refer to )
)Next▼
7.
Adjustment, repair, or replacement
Next▼
Complete
CHECKING / CLEARING DIAGNOSTIC CODES
1. Checking diagnostic codes (with the SSM3)
(1) DTC check for the main body ECM (Multiplex network body computer)
(a) Connect SSM3 to the data link connector with IG OFF.
(b) Turn IG to ON, and turn on the SSM3.
(c) Follow the instruction on SSM3 screen. Select [Each System Check]→[Integ. unit mode]→[Diagnostic Code(s) Display], and then read DTC.
NOTE:
If meaningless DTC is displayed, the main body ECM (Multiplex network body computer) may be defective.
(2) DTC check for the collation ECM (smart key computer ASSY)
(a) Connect SSM3 to the data link connector with IG OFF.
(b) Turn IG to ON, and turn on the SSM3.
(c) Follow the instruction on SSM3 screen. Select [Each System Check]→[Keyless access system]→[Collation ECM]→[Diagnostic Code(s) Display], and then read DTC.
NOTE:
·Collation ECM (Smart key computer ASSY) also outputs DTCs for the steering lock ECM (Steering lock actuator ASSY).
·If meaningless DTC is displayed, the collation ECM (Smart key computer ASSY) may be defective.
·If meaningless DTC is displayed, the collation ECM (Smart key computer ASSY) may be defective.
2. Clearing of recorded diagnostic codes (with the SSM3)
CAUTION:
To permanently clear DTCs indicating lost connection, “Clear ECM connection history” function must be used.
(1) Clearing DTC for the main body ECM (Multiplex network body computer)
(a) Connect SSM3 to the data link connector with IG OFF.
(b) Turn IG to ON, and turn on the SSM3.
(c) Follow the instruction on SSM3 screen. Select [Each System Check]→[Integ. unit mode]→[Clear Memory], and then clear DTC.
CAUTION:
·If deletion is not possible, retry it after turning the ignition to IG OFF and then on again.
·Do not use the SSM3 to delete diagnostic codes until the cause of the trouble has been identified.
·Do not use the SSM3 to delete diagnostic codes until the cause of the trouble has been identified.
(2) Clearing DTC for the collation ECM (Smart key computer ASSY)
(a) Connect SSM3 to the data link connector with IG OFF.
(b) Turn IG to ON, and turn on the SSM3.
(c) Follow the instruction on SSM3 screen. Select [Each System Check]→[Keyless access system]→[Collation ECM]→[Clear Memory], and then clear DTC.
CAUTION:
·If deletion is not possible, retry it after turning the ignition to IG OFF and then on again.
·Do not use the SSM3 to delete diagnostic codes until the cause of the trouble has been identified.
·Do not use the SSM3 to delete diagnostic codes until the cause of the trouble has been identified.
CIRCUIT FIGURE
1. Door system LIN communication circuit
2. Collation system LIN communication circuit (with smart entry and start system)
ECM TERMINAL ARRANGEMENT
1. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY AND MAIN BODY ECU (NETWORK GATEWAY ECU)
Text in Illustration
| *1 |
Instrument Panel Junction Block Assembly |
*2 |
Main Body ECU (Network Gateway ECU) |
(1) Remove the main body ECU (network gateway ECU) from the instrument panel junction block assembly. (See page )
)(2) Measure the voltage and resistance according to the value(s) in the table below.
Standard value
If the result is not as specified, there may be a malfunction in the wire harness.| Terminal No. (Symbol) |
Terminal Description |
Switch Condition |
Specified Condition |
|---|---|---|---|
| MB-1 (BECU) - Body ground |
Battery power supply |
Always |
11 to 14V |
| MB-8 (IG) - Body ground |
Battery power supply |
Ignition switch ON |
11 to 14V |
| MB-11 (GND) - Body ground |
Ground |
Always |
Below 1Ω |
| MB-32 (BMPX) - Body ground |
Battery power supply |
Always |
11 to 14V |
(3) Install the main body ECU (network gateway ECU) onto the instrument panel junction block assembly.
(4) Measure the pulses according to the value(s) in the table below.
Standard value
If the result is not as specified, the main body ECU (network gateway ECU) or instrument panel junction block assembly may have a malfunction.| Terminal No. (Symbol) |
Terminal Description |
Switch Condition |
Specified Condition |
|---|---|---|---|
| D5-4 (LIN) - D6-1 (GND) |
LIN Communication line |
Ignition switch ON |
Pulse generation |
2. CHECK POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY
Text in Illustration
| *1 |
for RHD |
*2 |
for LHD |
(1) Disconnect the F6*1 or E8*2 power window regulator master switch assembly connector.
(2) Measure the voltage and resistance according to the value(s) in the table below.
Standard value
If the result is not as specified, there may be a malfunction in the wire harness.| Terminal No. (Symbol) |
Terminal Description |
Switch Condition |
Specified Condition |
|---|---|---|---|
| F6-5 (GND) - Body ground*1 |
Ground |
Always |
Below 1Ω |
| E8-5 (GND) - Body ground*2 |
|||
| F6-12 (+B) - Body ground*1 |
Battery power supply |
Always |
11 to 14V |
| E8-12 (+B) - Body ground*2 |
·*1 : for RHD
·*2 : for LHD
·*2 : for LHD
3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (w/ Entry and Start System)
(1) Disconnect the D41 and D48 certification ECU (smart key ECU assembly) connectors.
(2) Measure the voltage and resistance according to the value(s) in the table below.
(3) Connect the D41 and D48 certification ECU (smart key ECU assembly) connectors.
(4) Measure the voltage according to the value(s) in the table below.
Standard value
If the result is not as specified, there may be a malfunction in the wire harness.| Terminal No. (Symbol) |
Terminal Description |
Switch Condition |
Specified Condition |
|---|---|---|---|
| D41-5 (IG2) - D48-11 (GND) |
Battery power supply |
Ignition switch ON |
11 to 14V |
4. CHECK STEERING LOCK ACTUATOR ASSEMBLY (w/ Entry and Start System)
(1) Disconnect the D59 steering lock actuator assembly connector.
(2) Measure the voltage and resistance according to the value(s) in the table below.
Standard value
If the result is not as specified, there may be a malfunction in the wire harness.| Terminal No. (Symbol) |
Terminal Description |
Switch Condition |
Specified Condition |
|---|---|---|---|
| D59-1 (GND) - Body ground |
Ground |
Always |
Below 1Ω |
| D59-6 (IGN1) - D59-1 (GND) |
Battery power supply |
Ignition switch ON |
11 to 14V |
| D59-7 (B) - D59-1 (GND) |
Battery power supply |
Always |
11 to 14V |
5. CHECK ID CODE BOX (IMMOBILISER CODE ECU) (w/ Entry and Start System with ID Code Box)
(1) Disconnect the A30 ID code box (immobiliser code ECU) connector.
(2) Measure the voltage and resistance according to the value(s) in the table below.
Standard value
If the result is not as specified, there may be a malfunction in the wire harness.| Terminal No. (Symbol) |
Terminal Description |
Switch Condition |
Specified Condition |
|---|---|---|---|
| A30-1 (+B) - A30-5 (GND) |
Battery power supply |
Always |
11 to 14V |
| A30-5 (GND) - Body ground |
Ground |
Always |
Below 1Ω |
| DTC | B2321 | Lost communication with Driver's P/W ECM |
|---|
Circuit description
B2321 is output when the communication between the main body ECM (Multiplex network body computer) ←→ the power window regulator master switch ASSY is interrupted for 10 seconds or more.
| DTC No. |
Detecting conditions |
Inspection parts |
|---|---|---|
| B2321 |
The periodic transmission from the power windows regulator master switch ASSY is interrupted for 10 seconds or more |
·Power window regulator master switch ASSY ·Main body ECM (Multiplex network body computer) ·Wiring harness or connector |
Circuit figure
Inspection steps
CAUTION:
Before performing troubleshooting, check the fuse for this circuit.
NOTE:
DTC B2325 is output when all ECMs connected to the door system LIN bus cannot communicate with the main body ECM (Multiplex network body computer).
1.
Clearing diagnostic code
(1) Clear the diagnostic code using the SSM3. (Refer to )
)Next▼
2.
DTC check
B
>Go to “How to simulate trouble phenomenon”. (Refer to)
)A▼
3.
Checking of the wiring harness and connector (Main body ECM (Multiplex network body computer) - Power window regulator master switch ASSY)
(1) Disconnect the connector D5 from the main body ECM (Multiplex network body computer).
(2) Disconnect the F6*1 or E8*2 power window regulator master switch assembly connector.
(3) Measure the resistance between the terminals.
(4) Reconnect the connector D5 to the main body ECM (multiplex network body computer).
·*1 : for RHD
·*2 : for LHD
·*2 : for LHD
NG
>Repair or replacement of wiring harness or connector
OK▼
4.
Checking of the power window regulator master switch ASSY (Power supply system)
(1) Measure the resistance and voltage between terminals.
Resistance
| Inspection terminals |
Inspection conditions |
Standard value |
|---|---|---|
| F6-5 - body ground *1 |
Always |
Less than 1 Ω |
| E8-5 - body ground *2 |
Always |
Less than 1 Ω |
Voltage
| Inspection terminals |
Inspection conditions |
Standard value |
|---|---|---|
| F6-12 - body ground *1 |
Always |
11 to 14V |
| E8-12 - body ground *2 |
Always |
11 to 14V |
Captions in illustration
| *a |
Front side of vehicle wiring harness connector (Power window regulator master switch ASSY connector) (RHD) *1 |
| *b |
Front side of vehicle wiring harness connector (Power window regulator master switch ASSY connector) (LHD) *2 |
·*1 : for RHD
·*2 : for LHD
·*2 : for LHD
NG
>Repair or replacement of wiring harness or connector
OK▼
5.
Replacement with a new power window regulator master switch ASSY
(1) Replace the power window regulator master switch ASSY with a new one. (Refer to )
)(2) Clear the diagnostic code using the SSM3. (Refer to )
)Next▼
| DTC | B2325 | Door system LIN communication bus error |
|---|
Circuit description
The main body ECM (Multiplex network body computer) monitors the communication between all ECMs connected to the door system LIN bus. If the main body ECM (Multiplex network body computer) detects communication errors with all the ECMs connected to the door system LIN bus, it counts the number of communication errors at 2.6 second interval. When it detects the errors three times consecutively, DTC B2325 is output.
| DTC No. |
Detecting conditions |
Inspection items |
|---|---|---|
| B2325 |
Main body ECM (Multiplex network body computer) detects the door system LIN bus communication errors three times consecutively |
·Power window regulator master switch ASSY ·Power window regulator switch ASSY ·Main body ECM (Multiplex network body computer) ·Wiring harness or connector |
Circuit figure
Inspection steps
1.
Clearing diagnostic code
(1) Clear the diagnostic code using the SSM3. (Refer to )
)Next▼
2.
DTC check
B
>Go to “How to simulate trouble phenomenon”. (Refer to)
)A▼
3.
Checking of the wiring harness and connector (Main body ECM (Multiplex network body computer) - Power window regulator master switch ASSY)
(1) Disconnect the connector D5 from the main body ECM (Multiplex network body computer).
(2) Disconnect the F6*1 or E8*2 power window regulator master switch assembly connector.
(3) Measure the resistance between the terminals.
(4) Reconnect the connector D5 to the main body ECM (multiplex network body computer).
·*1 : for RHD
·*2 : for LHD
·*2 : for LHD
NG
>Repair or replacement of wiring harness or connector
OK▼
4.
Checking of the power window regulator master switch ASSY (Power supply system)
(1) Measure the resistance and voltage between terminals.
Resistance
| Inspection terminals |
Inspection conditions |
Standard value |
|---|---|---|
| F6-5 - body ground *1 |
Always |
Less than 1 Ω |
| E8-5 - body ground *2 |
Always |
Less than 1 Ω |
Voltage
| Inspection terminals |
Inspection conditions |
Standard value |
|---|---|---|
| F6-12 - body ground *1 |
Always |
11 to 14V |
| E8-12 - body ground *2 |
Always |
11 to 14V |
Captions in illustration
| *a |
Front side of vehicle wiring harness connector (Power window regulator master switch ASSY connector) (RHD) *1 |
| *b |
Front side of vehicle wiring harness connector (Power window regulator master switch ASSY connector) (LHD) *2 |
·*1 : for RHD
·*2 : for LHD
·*2 : for LHD
NG
>Repair or replacement of wiring harness or connector
OK▼
5.
Replacement with a new power window regulator master switch ASSY
(1) Replace the multiplex network master switch ASSY with a new part. (Refer to )
)
(2) Clear the diagnostic code using the SSM3. (Refer to )
) Next▼
6.
DTC check
(1) Check DTC using SSM3.
Criteria
: B2325 is not output
NG
>Replacement of the main body ECM (Multiplex network body computer) (Refer to )
)OK▼
Complete (Failure of the power window regulator master switch ASSY)
| DTC | B2785 | LIN communication error |
|---|
Circuit description
The collation ECM (Smart key computer ASSY) monitors the communication with the steering lock actuator ASSY connected to the collation system LIN bus. If the collation ECM (Smart key computer ASSY) detects an error in the communication with the steering lock actuator ASSY connected to the collation system LIN bus, it monitors the communication errors for a certain period of time. When it detects error continuing for 1 second or more, DTC B2785 is output.
| DTC No. |
Detecting conditions |
Faulty part |
|---|---|---|
| B2785 |
When the collation ECM (Smart key computer ASSY) detected the collation system LIN bus communication error continuing for 3 times |
·Collation ECM (Smart key computer ASSY) ·Steering lock actuator ASSY ·ID code box (Immobilizer code ECM)* ·Wiring harness or connector |
*: with ID code box
Circuit figure
Inspection steps
CAUTION:
To replace the collation ECM (Smart key computer ASSY), the steering lock actuator ASSY and the ID code box, refer to the “Immobilizer Registration Manual”.
1.
Clearing diagnostic code
(1) Clear the diagnostic code using the SSM3. (Refer to )
)Next▼
2.
DTC check
B
>Go to “How to simulate trouble phenomenon”. (Refer to)
)A▼
3.
Checking of the LIN communication line (Collation ECM (Smart key computer ASSY) - Steering lock actuator ASSY)
(1) Disconnect the connector D41 from the collation ECM (Smart key computer ASSY).
(2) Disconnect the connector D59 from the steering lock actuator ASSY.
(3) Disconnect the connector A30 from the ID code box (Immobilizer code ECM)*.
(4) Measure the resistance between the terminals.
(5) Reconnect the connector D41 to the collation ECM (Smart key computer ASSY).
*: with ID code box
NG
>Repair or replacement of wiring harness or connector
OK▼
4.
DTC check (Steering lock actuator ASSY)
(2) Reconnect the connector D59 to the steering lock actuator ASSY.
B
>Replacement of the collation ECM (Smart key computer ASSY)
A▼
5.
Replacement of the steering lock actuator ASSY connector or ID code box (with ID code box)
(1) Replace the collation ECM (Smart key computer ASSY) or ID code box* with a new part.
(2) Clear the diagnostic code using the SSM3. (Refer to )
)*: with ID code box
Next▼
6.
Rechecking the diagnostic codes
B
>Replacement of the collation ECM (Smart key computer ASSY)
A▼
Complete (Failure of the steering lock actuator ASSY connector or ID code box (with ID code box))
| DTC | B2786 | No response from steering lock ECM |
|---|
Circuit description
·The collation ECM (Smart key computer ASSY) maintains LIN communication with the steering lock actuator ASSY.
·The collation ECM (Smart key computer ASSY) outputs this DTC when the communication with the steering lock actuator ASSY has been interrupted for 10 seconds or more.
·The collation ECM (Smart key computer ASSY) outputs this DTC when the communication with the steering lock actuator ASSY has been interrupted for 10 seconds or more.
| DTC No. |
Detecting conditions |
Inspection parts |
|---|---|---|
| B2786 |
LIN communication error between the collation ECM (Smart key computer ASSY) and the steering lock actuator ASSY |
·Wiring harness or connector ·Collation ECM (Smart key computer ASSY) ·Steering lock actuator ASSY |
Circuit figure
Inspection steps
CAUTION:
·To replace the collation ECM (Smart key computer ASSY) and the steering lock actuator ASSY, refer to the “Immobilizer Registration Manual”.
·Before performing troubleshooting, check the fuse for this circuit.
·Before performing troubleshooting, check the fuse for this circuit.
1.
DTC check
B
>Go to “List of diagnostic codes” (Refer to )
)A▼
2.
Checking of the LIN communication line (Collation ECM (Smart key computer ASSY) - Steering lock actuator ASSY)
(1) Disconnect the connector D41 from the collation ECM (Smart key computer ASSY).
(2) Disconnect the connector D59 from the steering lock actuator ASSY.
(3) Measure the resistance between the terminals.
(4) Reconnect the connector D41 to the collation ECM (Smart key computer ASSY).
NG
>Repair or replacement of wiring harness or connector
OK▼
3.
Checking of the wiring harness and connector (Power supply system)
(1) Measure the resistance and voltage between terminals.
Captions in illustration
| *a |
Front side of vehicle wiring harness connector (Steering lock actuator ASSY connector) |
NG
>Repair or replacement of wiring harness or connector
OK▼
4.
Replacement with a new steering lock actuator ASSY
(1) Replace the steering lock actuator ASSY with a new part. (Refer to )
)(2) Clear the diagnostic code using the SSM3. (Refer to )
)Next▼
| DTC | B2789 | No response from the ID code box |
|---|
Circuit description
·The collation ECM (Smart key computer ASSY) maintains LIN communication with the ID code box.
·The collation ECM (Smart key computer ASSY) outputs this DTC when the communication with the steering lock actuator ASSY has been interrupted for 10 seconds or more.
·The collation ECM (Smart key computer ASSY) outputs this DTC when the communication with the steering lock actuator ASSY has been interrupted for 10 seconds or more.
| DTC No. |
Detecting conditions |
Inspection parts |
|---|---|---|
| B2786 |
LIN communication error between the collation ECM (Smart key computer ASSY) and the ID code box |
·Wiring harness or connector ·Collation ECM (Smart key computer ASSY) ·ID code box |
Circuit figure
Inspection steps
CAUTION:
·To replace the collation ECM (Smart key computer ASSY), the steering lock actuator ASSY and the ID code box, refer to the “Immobilizer Registration Manual”.
·Before performing troubleshooting, check the fuse for this circuit.
·Before performing troubleshooting, check the fuse for this circuit.
1.
DTC check
B
>Go to “List of diagnostic codes” (Refer to )
)A▼
2.
Checking of the LIN communication line (Collation ECM (Smart key computer ASSY) - Steering lock actuator ASSY)
(1) Disconnect the connector D41 from the collation ECM (Smart key computer ASSY).
(2) Disconnect the connector A30 of the ID code box.
(3) Measure the resistance between the terminals.
(4) Reconnect the connector D41 to the collation ECM (Smart key computer ASSY).
NG
>Repair or replacement of wiring harness or connector
OK▼
3.
Checking of the wiring harness and connector (Power supply system)
(1) Measure the resistance and voltage between terminals.
Captions in illustration
| *a |
Front side of vehicle wiring harness connector (ID code box connector) |
NG
>Repair or replacement of wiring harness or connector
OK▼
4.
Replacement with a new ID code box
(1) Replace the ID code box with a new part.
(2) Clear the diagnostic code using the SSM3. (Refer to )
)Next▼