Power Management2

NETWORKING: CAN COMMUNICATION SYSTEM: U1002: Lost Communication with Gateway Module (Power Management2)
U1002 - Lost Communication with Gateway Module (Power Management2)

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 power management bus.

* When the power management control ECU receives a response signal from the ECUs connected to the power management bus, the power management control ECU recognizes and memorizes that the ECU is connected to the power management bus. Based on this memorized data, the power management control ECU monitors for malfunctions in the ECUs connected to the power management 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 power management 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 Management2).

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 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) Disconnect the cable from the negative (-) battery terminal.

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

Standard Resistance:

Result:

B -- CHECK FOR OPEN IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU)

C -- CHECK FOR SHORT IN CAN BUS WIRES (POWER MANAGEMENT CONTROL ECU)

D -- CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 4 J/C)
A -- Continue to next step.

2. CHECK DTC OUTPUT

(a) Clear the DTCs.

(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 Removal

3. CHECK FOR OPEN IN CAN 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 OPEN IN CAN BUS WIRE (ECM)

OK -- REPLACE POWER MANAGEMENT CONTROL ECU Removal

4. CHECK FOR OPEN IN CAN BUS WIRE (ECM)

(a) Reconnect the power management control ECU connector.

(b) Disconnect the ECM connector.

Text in Illustration

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

OK -- REPLACE ECM Removal

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

(a) Reconnect the ECM connector.

(b) Disconnect the CAN No. 4 junction connector.

Text in Illustration

Result:

B -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)

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

A -- REPLACE CAN NO. 4 JUNCTION CONNECTOR

6. CHECK FOR SHORT IN CAN BUS WIRES (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 BUS WIRES (ECM)

OK -- REPLACE POWER MANAGEMENT CONTROL ECU Removal

7. CHECK FOR SHORT IN CAN BUS WIRES (ECM)

(a) Reconnect the power management control ECU connector.

(b) Disconnect the ECM connector.

Text in Illustration

NG -- CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 4 J/C MAIN WIRE)

OK -- REPLACE ECM Removal

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

(a) Reconnect the ECM connector.

(b) Disconnect the CAN No. 4 junction connector.

Text in Illustration

Result:

B -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)

C -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 4 J/C - ECM)
A -- Continue to next step.

9. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 4 J/C - SKID CONTROL ECU)

(a) Disconnect the skid control ECU (brake booster with master cylinder) connector.

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

Standard Resistance:

Text in Illustration

NG -- REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 4 J/C - SKID CONTROL ECU)
OK -- Continue to next step.

10. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 4 J/C - A/C ECU)

(a) Disconnect the air conditioning amplifier connector.

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

Standard Resistance:

Text in Illustration

NG -- REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 4 J/C - A/C ECU)
OK -- Continue to next step.

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

(a) Reconnect the CAN No. 4 junction connector.

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

Standard Resistance:

Text in Illustration

NOTICE:
* The resistance must be measured after the ECM and CAN No. 4 J/C wire harness connector are reconnected.
* The resistance must be measured after the skid control ECU and air conditioning amplifier connector are disconnected.

NG -- REPLACE CAN NO. 4 JUNCTION CONNECTOR
OK -- Continue to next step.

12. CHECK FOR SHORT IN CAN BUS WIRES (AIR CONDITIONING AMPLIFIER)

(a) Reconnect the air conditioning amplifier connector.

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

Standard Resistance:

Text in Illustration

NOTICE:
* The resistance must be measured after the air conditioning amplifier connector is reconnected.
* The resistance must be measured after the skid control ECU connector is disconnected.

NG -- REPLACE AIR CONDITIONING AMPLIFIER Removal

OK -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER (SKID CONTROL ECU) Removal

13. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 4 J/C)

(a) Disconnect the CAN No. 4 junction connector.

(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 Bus Wire inspection.
* Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check CAN Bus Wire inspection.

Text in Illustration

NG -- CHECK FOR SHORT IN CAN BUS WIRES (ECU)

OK -- REPLACE CAN NO. 4 JUNCTION CONNECTOR

14. CHECK FOR SHORT IN CAN BUS WIRES (ECU)

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

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

Standard Resistance:

Text in Illustration

HINT
* It is only necessary to perform the inspection in the above table for the result (open or short circuit) that was obtained in the Check CAN Bus Wire inspection.
Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check CAN Bus Wire inspection.
* If the resistance changes to normal when the connector is disconnected from the ECU, there may be a short in the ECU.

NG -- REPAIR OR REPLACE CORRESPONDING ECU WIRE

OK -- REPLACE CORRESPONDING ECU