Part 1
NETWORKING: CAN COMMUNICATION SYSTEM: U1002: Lost Communication with Gateway Module (Main Body)
U1002 - Lost Communication with Gateway Module (Main Body)
DESCRIPTION
* The main 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 the CAN MS bus.
* When the main body ECU receives a response signal from the ECUs connected to the CAN MS bus, the main body ECU recognizes and memorizes that the ECU is connected to the CAN MS bus. Based on this memorized data, the main body ECU monitors for malfunctions in the ECUs connected to the CAN MS bus when communicating with those ECUs. If the main body ECU cannot receive response signals from the ECUs that have been memorized as those connected to the CAN MS bus, the main body ECU determines that a malfunction exists.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
* Turn the power switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.
* Turn the power switch off before inspecting CAN bus wires for a ground short.
* After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.
* Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.
HINT
* Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
* 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
1. CHECK CAN MS BUS WIRE
(a) Turn the power switch off.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(c) Disconnect the cable from the negative (-) battery terminal.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
D -- CHECK FOR SHORT IN CAN MS BUS WIRE (TILT AND TELESCOPIC ECU)
C -- CHECK FOR SHORT IN CAN MS BUS WIRE (TILT AND TELESCOPIC ECU)
B -- CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (TILT AND TELESCOPIC ECU)
A -- REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Removal
2. CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (TILT AND TELESCOPIC ECU)
(a) Disconnect the tilt and telescopic ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (CAN NO. 8 J/C)
OK -- REPLACE MULTIPLEX TILT AND TELESCOPIC ECU
3. CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (CAN NO. 8 J/C)
(a) Reconnect the tilt and telescopic ECU connector.
(b) Disconnect the CAN No. 8 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
D -- CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (CAN NO. 6 J/C)
C -- CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (CAN NO. 7 J/C)
B -- REPAIR OR REPLACE CAN MS BUS MAIN WIRE OR CONNECTOR (CAN NO. 8 J/C - TILT AND TELESCOPIC ECU)
A -- REPLACE CAN NO. 8 JUNCTION CONNECTOR
4. CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (CAN NO. 7 J/C)
(a) Reconnect the CAN No. 8 junction connector.
(b) Disconnect the CAN No. 7 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
C -- CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (CAN NO. 6 J/C)
B -- REPAIR OR REPLACE CAN MS BUS MAIN WIRE OR CONNECTOR (CAN NO. 7 J/C - CAN NO. 8 J/C)
A -- REPLACE CAN NO. 7 JUNCTION CONNECTOR
5. CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (CAN NO. 6 J/C)
(a) Reconnect the CAN No. 7 junction connector (w/ Power back door system).
(b) Reconnect the CAN No. 8 junction connector (w/o Power back door system).
(c) Disconnect the CAN No. 6 junction connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
D -- CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (MAIN BODY ECU)
C -- REPAIR OR REPLACE CAN MS BUS MAIN WIRE OR CONNECTOR (CAN NO. 6 J/C - CAN NO. 8 J/C)
B -- REPAIR OR REPLACE CAN MS BUS MAIN WIRE OR CONNECTOR (CAN NO. 6 J/C - CAN NO. 7 J/C)
A -- REPLACE CAN NO. 6 JUNCTION CONNECTOR
6. CHECK FOR OPEN IN CAN MS BUS MAIN WIRE (MAIN BODY ECU)
(a) Reconnect the CAN No. 6 junction connector.
(b) Disconnect the main body ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- REPAIR OR REPLACE CAN MS BUS MAIN WIRE OR CONNECTOR (CAN NO. 6 J/C - MAIN BODY ECU)
OK -- REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Removal
7. CHECK FOR SHORT IN CAN MS BUS WIRE (TILT AND TELESCOPIC ECU)
(a) Disconnect the tilt and telescopic ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 8 J/C)
OK -- REPLACE MULTIPLEX TILT AND TELESCOPIC ECU
8. CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 8 J/C)
(a) Reconnect the tilt and telescopic ECU connector.
(b) Disconnect the CAN No. 8 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
D -- CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 6 J/C)
C -- CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 7 J/C)
B -- REPAIR OR REPLACE CAN MS BUS MAIN WIRE OR CONNECTOR (CAN NO. 8 J/C - TILT AND TELESCOPIC ECU)
A -- Continue to next step.
9. CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 8 J/C - TIRE PRESSURE MONITOR ECU)
HINT
For vehicles without the tire pressure warning system, go to the next step.
(a) Disconnect the tire pressure monitor 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 MS BUS BRANCH WIRE OR CONNECTOR (CAN NO. 8 J/C - TIRE PRESSURE MONITOR ECU)
OK -- Continue to next step.
10. CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 8 J/C - OUTER MIRROR CONTROL ECU RH)
(a) Disconnect the outer mirror control ECU RH connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NG -- REPAIR OR REPLACE CAN MS BUS BRANCH WIRE OR CONNECTOR (CAN NO. 8 J/C - OUTER MIRROR CONTROL ECU RH)
OK -- Continue to next step.
11. CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 8 J/C)
(a) Reconnect the CAN No. 8 junction connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
NOTICE:
The resistance should only be measured when the ECUs connected to the CAN bus branch wires are disconnected, and the ECUs containing the terminating resistors are connected to the CAN main bus.
NG -- REPLACE CAN NO. 8 JUNCTION CONNECTOR
OK -- Continue to next step.
12. CHECK FOR SHORT IN CAN MS BUS WIRE (ECUS)
(a) Connect the probes of an ohmmeter to terminals F36-5 (CANP) and F36-14 (CANN) of the tilt and telescopic ECU.
Text in Illustration
(b) While observing the resistance value shown on the tester, reconnect the each ECU connector until the resistance becomes abnormal (Below 54 Ohms).
(c) Replace the ECU that caused the total resistance to drop below 54 Ohms when it was reconnected.
HINT
If the resistance becomes abnormal when an ECU connector is reconnected, there may be a short in the ECU.
NEXT -- REPLACE CORRESPONDING ECU
13. CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 7 J/C)
(a) Reconnect the CAN No. 8 junction connector.
(b) Disconnect the CAN No. 7 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
C -- CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 6 J/C)
B -- REPAIR OR REPLACE CAN MS BUS MAIN WIRE OR CONNECTOR (CAN NO. 7 J/C - CAN NO. 8 J/C)
A -- Continue to next step.
14. CHECK FOR SHORT IN CAN MS BUS WIRE (CAN NO. 7 J/C - POWER BACK DOOR ECU)
(a) Disconnect the power back door 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 MS BUS BRANCH WIRE OR CONNECTOR (CAN NO. 7 J/C - POWER BACK DOOR ECU)
OK -- Continue to next step.