Lost Communication with Gateway Module (Power Management1) - CAN Communication System

NETWORKING: CAN COMMUNICATION SYSTEM: U1002: Lost Communication with Gateway Module (Power Management1)
U1002 - Lost Communication with Gateway Module (Power Management1)

DESCRIPTION

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

HINT
The diagnosis procedure is for when DTC U1002 is output by the power management control ECU (Techstream display: Power Management1).

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 NO. 2 BUS WIRE

(a) Turn the power switch off.

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

Standard Resistance:

Text in Illustration

(c) Disconnected the cable from the negative (-) battery terminal.

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

Standard Resistance:

Result:

D -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (POWER MANAGEMENT CONTROL ECU)

C -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (POWER MANAGEMENT CONTROL ECU)

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

2. CHECK CAN BUS BRANCH WIRE

HINT
For vehicles with the dynamic radar cruise control system, go to the next step.

(a) For vehicles without the dynamic radar cruise control system:

(1) Check for the parking assist ECU branch wire and ECU power source circuit U110B.

NG -- REPAIR OR REPLACE WIRE HARNESS
OK -- Continue to next step.

3. CHECK DTC OUTPUT

(a) Clear the DTC.

(b) Turn the power switch off.

(c) Turn the power switch on (IG), recheck the DTC.

Result:

B -- GO TO CIRCUITS INDICATED BY OUTPUT DTCS

A -- REPLACE POWER MANAGEMENT CONTROL ECU

4. CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (POWER MANAGEMENT CONTROL ECU MAIN WIRE)

(a) Disconnect the power management control ECU connector.

Text in Illustration

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

Standard Resistance:

NG -- CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (CAN NO. 3 J/C)

OK -- REPLACE POWER MANAGEMENT CONTROL ECU

5. CHECK FOR OPEN IN CAN NO. 2 BUS MAIN WIRE (CAN NO. 3 J/C)

(a) Reconnect the power management control ECU connector.

(b) Disconnect the power management control ECU main wire connector from the CAN No. 3 junction connector.

Text in Illustration

NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 3 J/C - POWER MANAGEMENT CONTROL ECU)

OK -- REPLACE CAN NO. 3 JUNCTION CONNECTOR

6. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (POWER MANAGEMENT CONTROL ECU)

(a) Disconnect the power management control ECU connector.

Text in Illustration

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

Standard Resistance:

NG -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 3 J/C - POWER MANAGEMENT CONTROL ECU)

OK -- REPLACE POWER MANAGEMENT CONTROL ECU

7. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 3 J/C - POWER MANAGEMENT CONTROL ECU)

(a) Reconnect the power management control ECU connector.

(b) Disconnect the power management control ECU main wire connector from the CAN No. 3 junction connector.

Text in Illustration

NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 3 J/C - POWER MANAGEMENT CONTROL ECU)
OK -- Continue to next step.

8. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 3 J/C)

(a) Reconnect the power management control ECU main wire connector to the CAN No. 3 junction connector.

(b) Connect the probes of an ohmmeter to terminals 34 (CA2H) and 35 (CA2L) of the power management control ECU.

Text in Illustration

(c) While observing the resistance value shown on the ohmmeter, disconnect branch wire connectors (except L97) from the CAN No. 3 junction connector until the resistance becomes normal (between 54 and 69 Ohms).

Text in Illustration

HINT
* The connectors connected to the CAN junction connector can be distinguished by the colors of the bus wire.
* Reconnecting the connectors to non-specified positions on the CAN junction connector does not affect system operation.

Result:

B -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (ECUS)

A -- REPLACE CAN NO. 3 JUNCTION CONNECTOR

9. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (ECUS)

(a) Reconnect the connector for the short-circuited branch wire to the CAN junction connector (the connector that caused the bus wire resistance to become normal (between 54 and 69 Ohms) when it was disconnected).

(b) Disconnect the connector that includes terminals CANH and CANL from the ECU to which the short-circuited branch wire is connected.

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

Standard Resistance:

Text in Illustration

HINT
If the resistance becomes normal (between 54 and 69 Ohms) when the connector is disconnected from the ECU, there may be a short in the ECU.

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

OK -- REPLACE CORRESPONDING ECU OR SENSOR

10. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (POWER MANAGEMENT CONTROL ECU)

(a) Disconnect the power management control ECU connector.

Text in Illustration

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

Standard Resistance:

HINT
It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check CAN No. 2 Bus Wire inspection.

Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check CAN No. 2 Bus Wire inspection.

NG -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 3 J/C - POWER MANAGEMENT CONTROL ECU)

OK -- REPLACE POWER MANAGEMENT CONTROL ECU

11. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 3 J/C - POWER MANAGEMENT CONTROL ECU)

(a) Disconnect the power management control ECU main wire connector from the CAN No. 3 junction connector.

Text in Illustration

(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 (CAN NO. 3 J/C - POWER MANAGEMENT CONTROL ECU)
OK -- Continue to next step.

12. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (CAN NO. 3 J/C)

(a) Reconnect the power management control ECU main wire connector to the CAN No. 3 junction connector.

(b) Connect the probes of an ohmmeter to terminals CANH or CANL and GND or +B (AM22) of the power management control ECU.

Text in Illustration

HINT
It is only necessary to perform the inspection for the result (short circuit) that was obtained in the Check CAN No. 2 Bus Wire inspection.

(c) While observing the resistance value shown on the ohmmeter, disconnect branch wire connector (except L97) from the CAN No. 3 junction connector until the resistance becomes normal (6 kOhms or higher (for +B short) or 200 Ohms or higher (for ground short)).

Text in Illustration

B -- CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (ECUS)

A -- REPLACE CAN NO. 3 JUNCTION CONNECTOR

13. CHECK FOR SHORT IN CAN NO. 2 BUS WIRE (ECUS)

(a) Reconnect the connector for the bus wire that is shorted to +B or GND to the CAN junction connector (the connector that caused the bus wire resistance to change to 6 kOhms or higher (for +B short) or 200 Ohms or higher (for ground short) when it was disconnected).

(b) Disconnect the connector that includes terminals CANH and CANL from the ECU to which the bus wire shorted to +B or GND is connected.

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

Standard Resistance:

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

OK -- REPLACE CORRESPONDING ECU OR SENSOR