CAN COMMUNICATION SYSTEM, Diagnostic DTC:U1002

DTC Code DTC Name
U1002 Lost Communication with Gateway Module (Power Management2)

DESCRIPTION


DTC No. DTC Detection Condition Trouble Area
U1002 Power management control ECU cannot receive signals from all ECUs that have been memorized as those connected to the power management bus.

  • Open or short in power management bus main wire or connector

  • Open or short in power management bus branch wire or connector

  • Power management control ECU

  • ECM

  • Air conditioning amplifier

  • Skid control ECU (Brake booster with master cylinder)

  • CAN No. 4 junction connector

Tech Tips

The diagnosis procedure is for when DTC U1002 is output by the power management control ECU (Intelligent tester display: Power Management2).

WIRING DIAGRAM

A01JB72E01

INSPECTION PROCEDURE

Note


  • 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.

Tech Tips


  • 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


    1. Turn the power switch off.

    2. A01JAKSE23
      Text in Illustration
      *1

      Component with harness connector

      (Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Result
      L6-31 (CA3P) - L6-30 (CA3N) Power switch off 54 to 69 Ω

      Below 54 Ω:

      Short circuit between bus lines

      70 Ω or higher:

      Open circuit in a main bus line
      L6-31 (CA3P) - L6-4 (E12) Power switch off 200 Ω or higher

      Below 200 Ω:

      CANH ground short
      L6-30 (CA3N) - L6-4 (E12) Power switch off 200 Ω or higher

      Below 200 Ω:

      CANL ground short

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition Result
      L6-31 (CA3P) - L6-7 (AM21) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANH +B short
      L6-30 (CA3N) - L6-7 (AM21) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANL +B short
      Result
      Result Proceed to
      OK A
      Open circuit in CAN main bus wire B
      Short circuit between bus lines C

      • Ground short

      • +B short

      		 D

    B

    CHECK FOR OPEN IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU) Click here

    C

    CHECK FOR SHORT IN CAN BUS WIRES (POWER MANAGEMENT CONTROL ECU) Click here

    D

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

    A

  2. CHECK DTC OUTPUT


    1. Clear the DTCs.

    2. Turn the power switch off.

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

      Result
      Result Proceed to

      U1002 is output from power management control ECU

      (Intelligent tester display/Power Management2)

      		 A
      Other DTC is output B

    B

    GO TO CIRCUITS INDICATED BY OUTPUT DTCS

    A

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

  3. CHECK FOR OPEN IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU)


    1. A01JBLQE07
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L6-31 (CA3P) - L6-30 (CA3N) Power switch off 108 to 132 Ω

    NG

    CHECK FOR OPEN IN CAN BUS WIRE (ECM) Click here

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

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


    1. Reconnect the power management control ECU connector.

    2. A01JCO3E25
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A57-12 (CANP) - A57-4 (CANN) Power switch off 108 to 132 Ω

    NG

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

    OK

    REPLACE ECM Click here

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


    1. Reconnect the ECM connector.

    2. A01JAQEE21
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 4 Junction Connector)
      *2 to Power Management Control ECU
      *3 to ECM

      Disconnect the CAN No. 4 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Connected to
      L101-12 (CANH) - L101-1 (CANL) Power switch off 108 to 132 Ω Power management control ECU
      L101-15 (CANH) - L101-4 (CANL) Power switch off 108 to 132 Ω ECM
      Result
      Result Proceed to
      OK A
      NG (to power management ECU main wire) B
      NG (to ECM main wire) C

    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)


    1. A01JBLQE07
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L6-31 (CA3P) - L6-30 (CA3N) Power switch off 108 to 132 Ω

    NG

    CHECK FOR SHORT IN CAN BUS WIRES (ECM) Click here

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

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


    1. Reconnect the power management control ECU connector.

    2. A01JCO3E25
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A57-12 (CANP) - A57-4 (CANN) Power switch off 108 to 132 Ω

    NG

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

    OK

    REPLACE ECM Click here

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


    1. Reconnect the ECM connector.

    2. A01JAQEE21
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 4 Junction Connector)
      *2 to Power Management Control ECU
      *3 to ECM

      Disconnect the CAN No. 4 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Connected to
      L101-12 (CANH) - L101-1 (CANL) Power switch off 108 to 132 Ω Power management control ECU
      L101-15 (CANH) - L101-4 (CANL) Power switch off 108 to 132 Ω ECM
      Result
      Result Proceed to
      OK A
      NG (to Power management ECU main wire) B
      NG (to ECM main wire) C

    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

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


    1. A01JBTQE10
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

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

    2. A01JAQEE22
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 4 Junction Connector)
      *2 to Skid Control ECU

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L101-14 (CANH) - L101-3 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 4 J/C - SKID CONTROL ECU)

    OK

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


    1. A01JCIOE23
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Air Conditioning Amplifier)

      Disconnect the air conditioning amplifier connector.

    2. A01JAQEE23
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 4 Junction Connector)
      *2 to Air Conditioning Amplifier

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L101-13 (CANH) - L101-2 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 4 J/C - A/C ECU)

    OK

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


    1. Reconnect the CAN No. 4 junction connector.

    2. A01JBLQE07
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L6-31 (CA3P) - L6-30 (CA3N) Power switch off 108 to 132 Ω

      Note


      • 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

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


    1. Reconnect the air conditioning amplifier connector.

    2. A01JBLQE07
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L6-31 (CA3P) - L6-30 (CA3N) Power switch off 108 to 132 Ω

      Note


      • 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.

      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER (SKID CONTROL ECU) Click here

    C

    REPLACE AIR CONDITIONING AMPLIFIER Click here

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER (SKID CONTROL ECU) Click here

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


    1. Disconnect the CAN No. 4 junction connector.

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

      A01JDACE01
      Standard Resistance
      Tester Connection Condition Specified Condition Purpose Connected to
      L101-12 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANH ground short Power management control ECU
      L101-1 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANL ground short
      L101-13 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANH ground short Air conditioning amplifier
      L101-2 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANL ground short
      L101-14 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANH ground short Skid control ECU
      L101-3 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANL ground short
      L101-15 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANH ground short ECM
      L101-4 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher Inspection for CANL ground short
      L101-12 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANH +B short Power management control ECU
      L101-1 (CANL) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANL +B short
      L101-13 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANH +B short Air conditioning amplifier
      L101-2 (CANL) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANL +B short
      L101-14 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANH +B short Skid control ECU
      L101-3 (CANL) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANL +B short
      L101-15 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANH +B short ECM
      L101-4 (CANL) - L61-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANL +B short

      Tech Tips


      • 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
      *1

      Front view of wire harness connector

      (to CAN No. 4 Junction Connector)

      		 *2 DLC3
      *3 to Power Management Control ECU *4 to Air Conditioning Amplifier
      *5 to Skid Control ECU *6 to ECM

    NG

    CHECK FOR SHORT IN CAN BUS WIRES (ECU) Click here

    OK

    REPLACE CAN NO. 4 JUNCTION CONNECTOR

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


    1. 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 Click here.

    2. A01JAKSE23
      Text in Illustration
      *1

      Component with harness connector

      (Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Purpose
      L6-31 (CA3P) - L6-4 (E12) Power switch off 200 Ω or higher

      Below 200 Ω:

      CANH ground short
      L6-30 (CA3N) - L6-4 (E12) Power switch off 200 Ω or higher

      Below 200 Ω:

      CANL ground short
      L6-31 (CA3P) - L6-7 (AM21) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANH +B short
      L6-30 (CA3N) - L6-7 (AM21) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANL +B short

      Tech Tips


      • 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