U1002

CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: U1002: Lost Communication with Gateway Module
U1002 - Lost Communication with Gateway Module

DESCRIPTION

* The gateway 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 No. 2 bus.

* When the gateway ECU receives response signals from the ECUs connected to the CAN No. 2 bus, the gateway ECU recognizes and memorizes that the ECUs are connected to the CAN No. 2 bus. Based on this memorized data, the gateway ECU monitors for malfunctions in the ECUs connected to the CAN No. 2 bus when communicating with those ECUs. If the gateway ECU cannot receive response signals from the ECUs that have been memorized as those connected to the CAN No. 2 bus, the gateway ECU determines that a malfunction exists.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
* Turn the engine switch off before measuring the resistance of CAN bus main wires and CAN bus branch wires.
* After the engine switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.
* Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the engine 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 engine switch, any switches, or any doors 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 will help to determine the cause of the malfunction.
PROCEDURE

1. CHECK CAN NO. 2 BUS WIRE

(a) Turn the engine switch off.

(b) Measure the resistance according to the value(s) in the table below.

Result:

C -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C)

B -- CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (GATEWAY ECU MAIN WIRE)
A -- Continue to next step.

2. CHECK FOR SHORT TO B+ IN CAN NO. 2 BUS WIRE

(a) Measure the resistance according to the value(s) in the table below.

Standard resistance:

NG -- CHECK FOR SHORT TO B+ IN CAN NO. 2 BUS WIRE (CAN NO. 4 J/C - GATEWAY ECU)
OK -- Continue to next step.

3. CHECK FOR SHORT TO GND IN CAN NO. 2 BUS WIRE

(a) Measure the resistance according to the value(s) in the table below.

Standard resistance:

NG -- CHECK FOR SHORT TO GND IN CAN NO. 2 BUS WIRE (CAN NO. 4 - GATEWAY ECU)
OK -- Continue to next step.

4. CHECK FOR CAN NO. 2 BUS BRANCH WIRE

(a) Check for an open in the branch wires of all ECUs connected to the CAN No. 2 bus.

(1) Check the AFS ECU branch wire U0182.

(2) Check the distance control ECU branch wire U1102.

(3) Check the seat belt control ECU branch wire U1100.

Result:

B -- REPAIR OR REPLACE MALFUNCTIONING PART

A -- REPLACE GATEWAY ECU

5. CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (GATEWAY ECU MAIN WIRE)

(a) Disconnect gateway ECU main wire connector E38 from the CAN No. 1 J/C.

HINT
* Before disconnecting the connector, make a note of where it is connected.
* Reconnect the connector to its original position.
(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:

OK -- CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (CAN NO. 4 J/C)
NG -- Continue to next step.

6. CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (GATEWAY ECU - CAN NO. 1 J/C)

(a) Reconnect gateway ECU main wire connector E38.

(b) Disconnect connector E25 from the gateway ECU.

NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (GATEWAY ECU - CAN NO. 1 J/C)

OK -- REPLACE GATEWAY ECU

7. CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (CAN NO. 4 J/C)

(a) Reconnect gateway ECU main wire connector E38.

(b) Disconnect CAN No. 1 J/C main wire connector E41.

HINT
* Before disconnecting the connector, make a note of where it is connected.
* Reconnect the connector to its original position.
(c) Measure the resistance according to the value(s) in the table below.

Standard resistance:

OK -- REPLACE CAN NO. 1 J/C
NG -- Continue to next step.

8. CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (CAN NO. 1 J/C - CAN NO. 4 J/C)

(a) Reconnect CAN No. 1 J/C main wire connector E41.

(b) Disconnect CAN No. 4 J/C main wire connector M15.

NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 4 J/C)

OK -- REPLACE CAN NO. 4 J/C

9. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C)

(a) Disconnect CAN No. 1 J/C main wire connector E41.

OK -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C WIRE)
NG -- Continue to next step.

10. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 4 J/C MAIN WIRE)

(a) Reconnect CAN No. 1 J/C main wire connector E41.

(b) Disconnect CAN No. 4 J/C main wire connector M15.

Result:

C -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 4 J/C)

B -- REPLACE CAN NO. 4 J/C
A -- Continue to next step.

11. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 4 J/C)

(a) Reconnect CAN No. 4 J/C main wire connector M15.

(b) Disconnect CAN No. 4 J/C branch wire connector M16.

(c) Disconnect CAN No. 1 J/C main wire connector E41.

(d) Measure the resistance according to the value(s) in the table below.

Standard resistance:

NG -- REPLACE CAN NO. 4 J/C
OK -- Continue to next step.

12. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 4 - SEAT BELT CONTROL ECU)

(a) Reconnect CAN No. 4 J/C branch wire connector M16.

(b) Disconnect the seat belt control ECU connector.

NG -- REPAIR OR REPLACE CAN NO. 2 BUS WIRE (CAN NO. 4 - SEAT BELT CONTROL ECU)

OK -- REPLACE SEAT BELT CONTROL ECU

13. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C WIRE)

(a) Reconnect CAN No. 1 J/C main wire connector E41.

(b) Connect the probes of an ohmmeter to terminals 1 (CANH) and 2 (CANL) of CAN No. 1 J/C main wire connector E41.

(c) While observing the resistance value shown on the tester, disconnect connectors E39 and E40 from the CAN No. 1 J/C one by one until the resistance becomes normal (between 54 and 69 Ohms).

HINT
Disconnect the branch wire connectors only.

Wiring color:

Wiring color::

NOTICE:
Do not reconnect the disconnected connectors until this inspection is complete because there may be a short in 2 or more branch wires.

HINT
(*1) : with dynamic radar cruise control system

Result:

(d) When there is a short in one or more of the branch wires:

(1) Reconnect all of the connectors to the CAN No. 1 J/C, except for the one that was disconnected last (the short-circuited bus wire). Check that the resistance shown on the tester is normal (between 54 and 69 Ohms) to confirm that there is a short in one branch wire only.

HINT
* The connectors connected to the CAN No. 1 J/C can be distinguished according to the color of the communication bus wires and the shape of the connectors.
* Reconnecting the connectors to non-specified positions on the CAN No. 1 J/C does not affect system operation. However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
B -- RECONNECT CONNECTOR
A -- Continue to next step.

14. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C)

(a) Disconnect gateway ECU main wire connector E38 from the CAN No. 1 J/C.

OK -- REPLACE CAN NO. 1 J/C
NG -- Continue to next step.

15. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C - GATEWAY ECU)

(a) Disconnect connector E25 from the gateway ECU.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:

NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (GATEWAY ECU - CAN NO. 1 J/C)

OK -- REPLACE GATEWAY ECU

16. CHECK FOR SHORT TO B+ IN CAN NO. 2 BUS WIRE (CAN NO. 4 J/C - GATEWAY ECU)

(a) Disconnect CAN No. 1 J/C main wire connector E41.

OK -- CHECK FOR SHORT TO B+ IN CAN NO. 2 BUS WIRE (CAN NO. 1 BRANCH WIRE)
NG -- Continue to next step.

17. CHECK FOR SHORT TO B+ IN CAN NO. 2 BUS WIRE (CAN NO. 4 MAIN WIRE)

(a) Reconnect CAN No. 1 J/C main wire connector E41.

(b) Disconnect CAN No. 4 J/C main wire connector M15.

Result:

C -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 4 J/C)

B -- REPLACE CAN NO. 4 J/C
A -- Continue to next step.

18. CHECK FOR SHORT TO B+ IN CAN NO. 2 BUS WIRE (SEAT BELT CONTROL ECU BRANCH WIRE)

(a) Disconnect seat belt control ECU branch wire connector M16.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:

NG -- RECONNECT CONNECTOR

OK -- REPLACE CAN NO. 4 J/C

19. CHECK FOR SHORT TO B+ IN CAN NO. 2 BUS WIRE (CAN NO. 1 BRANCH WIRE)

(a) Reconnect CAN No. 1 J/C main wire connector E41.

(b) Disconnect connectors from the CAN No. 1 J/C one at a time.

HINT
Disconnect the ECU and sensor connectors other than CAN No. 4 J/C main wire connector E41.

(c) Using an ohmmeter, measure the resistance between terminal 1 (CANH) of CAN No. 1 J/C main wire connector E41 and terminal 16 (BAT) of the DLC3, and between terminal 2 (CANL) of CAN No. 1 J/C main wire connector E41 and terminal 16 (BAT) of the DLC3 each time a connector is disconnected.

Wiring color:

Wiring color::

NOTICE:
Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to B+ in 2 or more CAN No. 2 bus wires.

HINT
(*1) : with dynamic radar cruise control system

Result:

(d) When there is a short to B+ in one or more of the bus wires that connect to an ECU (or sensor):

(1) Reconnect all of the connectors to the CAN No. 1 J/C, except for the one that was disconnected last (the bus wire that is shorted to B+). Check that the resistance shown on the tester is normal (6 kOhms or more) to confirm that there is a short to B+ in one bus wire only.

HINT
* The connectors connected to the CAN No. 1 J/C can be distinguished according to the color of the communication bus wires and the shape of the connectors.
* Reconnecting the connectors to non-specified positions on the CAN No. 1 J/C does not affect system operation. However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
B -- RECONNECT CONNECTOR

A -- REPLACE CAN NO. 1 J/C

20. CHECK FOR SHORT TO GND IN CAN NO. 2 BUS WIRE (CAN NO. 4 - GATEWAY ECU)

(a) Disconnect CAN No. 1 J/C main wire connector E41.

OK -- CHECK FOR SHORT TO GND IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C BRANCH WIRE)
NG -- Continue to next step.

21. CHECK FOR SHORT TO GND IN CAN NO. 2 BUS WIRE (CAN NO. 4 J/C)

(a) Reconnect CAN No. 1 J/C main wire connector E41.

(b) Disconnect CAN No. 4 J/C main wire connector M15.

Result:

C -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 4 J/C)

B -- REPLACE CAN NO. 4 J/C
A -- Continue to next step.

22. CHECK FOR SHORT TO GND IN CAN NO. 2 BUS WIRE (SEAT BELT ECU BRANCH WIRE)

(a) Disconnect seat belt control ECU branch wire connector M16.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:

NG -- RECONNECT CONNECTOR

OK -- REPLACE CAN NO. 4 J/C

23. CHECK FOR SHORT TO GND IN CAN NO. 2 BUS WIRE (CAN NO. 1 J/C BRANCH WIRE)

(a) Reconnect CAN No. 1 J/C main wire connector E41.

(b) Disconnect connectors from the CAN No. 1 J/C one at a time.

HINT
Disconnect the ECU and sensor connectors other than CAN No. 4 J/C main wire connector E41.

(c) Using an ohmmeter, measure the resistance between terminal 1 (CANH) of CAN No. 1 J/C main wire connector E41 and terminal 4 (CG) of the DLC3, and between terminal 2 (CANL) of CAN No. 1 J/C main wire connector E41 and terminal 4 (CG) of the DLC3 each time a connector is disconnected.

Wiring color:

Wiring color::

NOTICE:
Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to GND in 2 or more CAN No. 2 bus wires.

HINT
(*1) : with dynamic radar cruise control system

Result:

(d) When there is a short to GND in one or more of the bus wires that connect to an ECU (or sensor):

(1) Reconnect all of the connectors to the CAN No. 1 J/C, except for the one that was disconnected last (the bus wire that is shorted to GND). Check that the resistance shown on the tester is normal (200 Ohms or more) to confirm that there is a short to GND in one bus wire.

HINT
* The connectors connected to the CAN No. 1 J/C can be distinguished according to the color of the communication bus wires and the shape of the connectors.
* Reconnecting the connectors to non-specified positions on the CAN No. 1 J/C does not affect system operation. However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
A -- REPLACE CAN NO. 1 J/C
B -- Continue to next step.

24. RECONNECT CONNECTOR

(a) Reconnect the connector for the short-circuited main or branch wire to the CAN No. 1 J/C or CAN No. 4 J/C (the connector that caused the bus wire resistance to become normal when it was disconnected).

NEXT -- Continue to next step.

25. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE

(a) Disconnect the connector of the ECU that is connected to the short-circuited main or branch wire from the ECU.

(b) Recheck the short-circuited wire with the connector disconnected from the ECU.

OK:

The wire is not short-circuited.

HINT
If the short-circuited wire returns to normal after being disconnected from the ECU, an internal short in the ECU is suspected.

NG -- REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH WIRE OR CONNECTOR

OK -- REPLACE CORRESPONDING ECU OR SENSOR