Part 1
NETWORKING: CAN COMMUNICATION SYSTEM: U1002: Lost Communication with Gateway Module (MS Bus)
U1002 - Lost Communication with Gateway Module (MS Bus)
DESCRIPTION
* The main body ECU (multiplex network body ECU) stores this DTC when no signals can be received from the ECUs that have been memorized as those connected to the MS bus.
* When the main body ECU (multiplex network body ECU) receives a response signal from the ECUs connected to the MS bus, the main body ECU (multiplex network body ECU) recognizes and memorizes that the ECU is connected to the MS bus. Based on this memorized data, the main body ECU (multiplex network body ECU) monitors for malfunctions in the ECUs connected to the MS bus 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 the MS bus, the main body ECU (multiplex network body ECU) determines that a malfunction exists.
* If 2 or more DTCs are output during the DTC check, one side of the CAN branch wire may be open (one side of the CANH [branch wire]/CANL [branch wire] of the ECU and/or sensor is open).
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT
Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
PROCEDURE
1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.
CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
NOTICE:
* w/ Navigation System:
After the engine switch is turned off, the display and navigation module display records various types of memory and settings. As a result, after turning the engine switch off, be sure to wait for the time specified in the following table before disconnecting the cable from the negative (-) battery terminal.
Waiting Time before Disconnecting Cable from Negative (-) Battery Terminal:
* When disconnecting the cable, some systems need to be initialized after the cable is reconnected Repair Instruction - Initialization.
NEXT -- Continue to next step.
2. CHECK FOR CAN BUS WIRE (MAIN WIRE FOR DISCONNECTION, BUS LINE FOR SHORT CIRCUIT)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result
C -- CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND GROUND)
B -- CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR SIDE)
A -- Continue to next step.
3. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 1 JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR)
(a) Disconnect the G84 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- Continue to next step.
4. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 1 JUNCTION CONNECTOR - NO. 6 JUNCTION CONNECTOR)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- REPLACE NO. 1 JUNCTION CONNECTOR
5. CONNECT CONNECTOR
(a) Reconnect the G84 No. 1 junction connector connector.
NEXT -- Continue to next step.
6. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 3 JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR)
(a) Disconnect the G81 No. 3 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 3 JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR)
OK -- Continue to next step.
7. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 3 JUNCTION CONNECTOR - MAIN BODY ECU)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- REPLACE NO. 3 JUNCTION CONNECTOR
8. CONNECT CONNECTOR
(a) Reconnect the G84 No. 1 junction connector connector.
NEXT -- Continue to next step.
9. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 6 JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR)
(a) Disconnect the G87 No. 6 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 6 JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR)
OK -- REPLACE NO. 6 JUNCTION CONNECTOR
10. CONNECT CONNECTOR
(a) Reconnect the G81 No. 3 junction connector connector.
NEXT -- Continue to next step.
11. CHECK FOR OPEN IN CAN BUS MAIN WIRE (MAIN BODY ECU - NO. 3 JUNCTION CONNECTOR)
(a) Disconnect the G46 main body ECU (multiplex network body ECU) connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO MAIN BODY ECU (MAIN BODY ECU - NO. 3 JUNCTION CONNECTOR)
OK -- REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Removal
12. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR SIDE)
(a) Disconnect the G81 No. 3 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- Continue to next step.
13. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - FRONT POWER SEAT SWITCH LH)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- Continue to next step.
14. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - MULTIPLEX TILT AND TELESCOPIC ECU)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- Continue to next step.
15. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - OUTER MIRROR CONTROL ECU LH)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- Continue to next step.
16. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - MAIN BODY ECU)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- REPLACE NO. 3 JUNCTION CONNECTOR
17. CONNECT CONNECTOR
(a) Reconnect the G81 No. 3 junction connector connector.
NEXT -- Continue to next step.
18. CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR)
(a) Disconnect the G84 No. 1 junction connector connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR)
OK -- Continue to next step.
19. CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 JUNCTION CONNECTOR - DRIVING SUPPORT SWITCH CONTROL ECU)
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CONNECT CONNECTOR
OK -- Continue to next step.