DTC Code | DTC Name |
---|---|
U1002 | Lost Communication with Gateway Module (Main Body ECU) |
DESCRIPTION
The main body ECU (multiplex network body ECU) will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to sub bus 1.
When the main body ECU (multiplex network body ECU) receives a response signal from the ECUs connected to sub bus 1, the main body ECU (multiplex network body ECU) recognizes and memorizes that the ECU is connected to sub bus 1. Based on this memorized data, the main body ECU (multiplex network body ECU) monitors for malfunctions in the ECUs connected to sub bus 1 when communicating with those ECUs. If the main body ECU (multiplex network body ECU) cannot receive response signals from the ECUs that have been memorized as those connected to sub bus 1, the main body ECU (multiplex network body ECU) determines that a malfunction exists.
DTC No. | Detection Item | DTC Detection Condition | Trouble Area | DTC Output from |
---|---|---|---|---|
U1002 | Lost Communication with Gateway Module (Main Body ECU) | The main body ECU (multiplex network body ECU) cannot receive signals from all ECUs that have been memorized as those connected to sub bus 1. |
|
Main body ECU (multiplex network body ECU) |
Tech Tips
This diagnostic procedure is for when DTC U1002 is output by the main body ECU (multiplex network body ECU) (GTS display: Main Body).
WIRING DIAGRAM
CAUTION / NOTICE / HINT
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Note
Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
Some parts must be initialized and set when replacing or removing and installing parts.
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.
Tech Tips
Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.
PROCEDURE
CHECK SUB BUS 1
Disconnect the cable from the negative (-) battery terminal.
*a | Component with harness connected (Main Body ECU [Multiplex Network Body ECU]) |
*b | Front view of DLC3 |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
B |
CHECK FOR OPEN IN CAN BUS WIRE (NO. 5 CAN JUNCTION CONNECTOR) Click here |
C |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR) Click here |
D |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR) Click here |
A |
CHECK FOR DTC OUTPUT
Reconnect the cable to the negative (-) battery terminal.
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off.
Turn the engine switch on (IG).
Check for DTCs.
Result | ||||||
---|---|---|---|---|---|---|
|
A |
SYMPTOM SIMULATION Click here |
B |
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: Click here |
CHECK FOR OPEN IN CAN BUS WIRE (NO. 5 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 5 CAN Junction Connector) |
*b | to No. 7 CAN Junction Connector |
*c | to No. 4 CAN Junction Connector |
Disconnect the No. 5 CAN junction connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | ||||||||
---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 5 CAN JUNCTION CONNECTOR |
C |
CONNECT CONNECTOR Click here |
B |
CONNECT CONNECTOR
Connect the I97 No. 5 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR OPEN IN CAN BUS WIRE (NO. 7 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 7 CAN Junction Connector) |
*b | to No. 5 CAN Junction Connector |
*c | to No. 2 CAN Junction Terminal |
Disconnect the No. 7 CAN junction connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | ||||||||
---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 7 CAN JUNCTION CONNECTOR |
C |
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR) |
B |
CONNECT CONNECTOR
Connect the Y22 No. 7 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR OPEN IN CAN BUS WIRE (NO. 2 CAN JUNCTION TERMINAL - NO. 7 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 2 CAN Junction Terminal) |
Disconnect the No. 2 CAN junction terminal connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
OK |
REPLACE NO. 2 CAN JUNCTION TERMINAL |
NG |
REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (NO. 2 CAN JUNCTION TERMINAL - NO. 7 CAN JUNCTION CONNECTOR) |
CONNECT CONNECTOR
Connect the I97 No. 5 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR OPEN IN CAN BUS WIRE (NO. 4 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | to Main Body ECU (Multiplex Network Body ECU) |
*c | to No. 5 CAN Junction Connector |
Disconnect the No. 4 CAN junction connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | ||||||||
---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 4 CAN JUNCTION CONNECTOR |
C |
REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR) |
B |
CONNECT CONNECTOR
Connect the I96 No. 4 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR OPEN IN CAN BUS WIRE (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - NO. 4 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to Main Body ECU [Multiplex Network Body ECU]) |
Disconnect the main body ECU (multiplex network body ECU) connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
OK |
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: Click here |
NG |
REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - NO. 4 CAN JUNCTION CONNECTOR) |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 5 CAN Junction Connector) |
*b | to Multiplex Tilt and Telescopic ECU (for LHD with Power Tilt and Power Telescopic Steering Column) |
*c | to No. 7 CAN Junction Connector |
*d | to No. 4 CAN Junction Connector |
*e | to Front Power Seat Switch (for Driver Side) (for LHD with Memory) |
*f | to Outer Mirror Control ECU Assembly LH (w/ Memory) |
Disconnect the No. 5 CAN junction connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
*2: for LHD with Memory *3: w/ Memory |
Result | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 5 CAN JUNCTION CONNECTOR |
C |
CONNECT CONNECTOR Click here |
D |
GO TO STEP 28 Click here |
B |
CONNECT CONNECTOR
Connect the I97 No. 5 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 7 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 7 CAN Junction Connector) |
*b | to No. 5 CAN Junction Connector |
*c | to Multiplex Network Door ECU (w/ Power Back Door System) |
*d | to No. 2 CAN Junction Terminal |
Disconnect the No. 7 CAN junction connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 7 CAN JUNCTION CONNECTOR |
C |
REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR) |
D |
GO TO STEP 28 Click here |
B |
CONNECT CONNECTOR
Connect the Y22 No. 7 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 CAN JUNCTION TERMINAL - NO. 7 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 2 CAN Junction Terminal) |
Disconnect the No. 2 CAN junction terminal connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
OK |
REPLACE NO. 2 CAN JUNCTION TERMINAL |
NG |
REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (NO. 2 CAN JUNCTION TERMINAL - NO. 7 CAN JUNCTION CONNECTOR) |
CONNECT CONNECTOR
Connect the I97 No. 5 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 4 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | to Multiplex Tilt and Telescopic ECU (for RHD with Power Tilt and Power Telescopic Steering Column) |
*c | to Main Body ECU (Multiplex Network Body ECU) |
*d | to Outer Mirror Control ECU Assembly RH (w/ Memory) |
*e | to Front Power Seat Switch (for Driver Side) (for RHD with Memory) |
*f | to No. 5 CAN Junction Connector |
Disconnect the No. 4 CAN junction connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
*2: w/ Memory *3: for RHD with Memory |
Result | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 4 CAN JUNCTION CONNECTOR |
C |
REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR) |
D |
GO TO STEP 28 Click here |
B |
CONNECT CONNECTOR
Connect the I96 No. 4 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR SHORT IN CAN BUS WIRES (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - NO. 4 CAN JUNCTION CONNECTOR)
*a | Rear view of wire harness connector (to Main Body ECU [Multiplex Network Body ECU]) |
Disconnect the main body ECU (multiplex network body ECU) connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
OK |
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: Click here |
NG |
REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - NO. 4 CAN JUNCTION CONNECTOR) |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR)
Disconnect the No. 5 CAN junction connector.
*a | Rear view of wire harness connector (to No. 5 CAN Junction Connector) |
*b | Front view of DLC3 |
*c | to Multiplex Tilt and Telescopic ECU (for LHD with Power Tilt and Power Telescopic Steering Column) | *d | to No. 7 CAN Junction Connector |
*e | to No. 4 CAN Junction Connector | *f | to Front Power Seat Switch (for Driver Side) (for LHD with Memory) |
*g | to Outer Mirror Control ECU Assembly LH (w/ Memory) | - | - |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
*2: for LHD with Memory *3: w/ Memory |
Result | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 5 CAN JUNCTION CONNECTOR |
C |
CONNECT CONNECTOR Click here |
D |
GO TO STEP 28 Click here |
B |
CONNECT CONNECTOR
Connect the I97 No. 5 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 7 CAN JUNCTION CONNECTOR)
Disconnect the No. 7 CAN junction connector.
*a | Rear view of wire harness connector (to No. 7 CAN Junction Connector) |
*b | Front view of DLC3 |
*c | to No. 5 CAN Junction Connector | *d | to Multiplex Network Door ECU (w/ Power Back Door System) |
*e | to No. 2 CAN Junction Terminal | - | - |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | ||||||||
---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 5 CAN JUNCTION CONNECTOR |
B |
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR) |
C |
GO TO STEP 28 Click here |
CONNECT CONNECTOR
Connect the I97 No. 5 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR SHORT IN CAN BUS WIRES (NO. 4 CAN JUNCTION CONNECTOR)
Disconnect the No. 4 CAN junction connector.
*a | Rear view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | Front view of DLC3 |
*c | to Multiplex Tilt and Telescopic ECU (for RHD with Power Tilt and Power Telescopic Steering Column) | *d | to Main Body ECU (Multiplex Network Body ECU) |
*e | to Outer Mirror Control ECU Assembly RH (w/ Memory) | *f | to Front Power Seat Switch (for Driver Side) (for RHD with Memory) |
*g | to No. 5 CAN Junction Connector | - | - |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
*2: w/ Memory *3: for RHD with Memory |
Result | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
A |
REPLACE NO. 4 CAN JUNCTION CONNECTOR |
B |
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR) |
D |
CHECK SHORT IN CAN BUS WIRES Click here |
C |
CONNECT CONNECTOR
Connect the I96 No. 4 CAN junction connector.
Result | ||
---|---|---|
|
Next |
CHECK FOR SHORT IN CAN BUS WIRES (MAIN BODY ECU)
*a | Rear view of wire harness connector (to Main Body ECU [Multiplex Network Body ECU]) |
*b | Front view of DLC3 |
Disconnect the main body ECU (multiplex network body ECU) connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
OK |
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: Click here |
NG |
REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO MAIN BODY ECU (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - NO. 4 CAN JUNCTION CONNECTOR) |
CHECK SHORT IN CAN BUS WIRES
Reconnect all wire harness connectors.
*a | Component with harness connected (Main Body ECU [Multiplex Network Body ECU]) |
*b | Front view of DLC3 |
Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line, +B or GND is connected.
Standard Resistance | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Tech Tips
If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
If the resistance changes to 6 kΩ or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
If the resistance changes to 200 Ω or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
Result | |||
---|---|---|---|
|
OK |
REPLACE CORRESPONDING ECU OR SENSOR |
NG |
REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BUS LINES OR CONNECTOR |