HYBRID BATTERY SYSTEM, Diagnostic DTC:U029A-123

DTC Code DTC Name
U029A-123 Lost Communication with Hybrid Battery Pack Sensor Module

DESCRIPTION

The battery smart unit detects the HV battery conditions (voltage, current, and temperature) and the battery cooling fan voltage, and sends the detected signals to the power management control ECU via serial communication. (The power management control ECU does not send signals to the battery smart unit.)

DTC No. DTC Detection Condition Trouble Area
U029A-123 Serial communication error between the battery smart unit and the power management control ECU (The power management control ECU did not receive signals from the battery smart unit.) (1 trip detection)

  • Wire harness or connector

  • Power management control ECU

  • Battery smart unit

WIRING DIAGRAM

A01JACJE01

INSPECTION PROCEDURE

CAUTION:


  • If the battery cover is removed, install it before turning the power switch on (IG) or (READY). If the power switch is turned on (IG) or (READY) with the battery cover removed, U029A-123 may be stored.

  • Before inspecting the high-voltage system, take safety precautions to prevent electrical shocks, such as wearing insulated gloves and removing the service plug grip. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.

  • After disconnecting the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals.

    Tech Tips

    At least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

Note

After the power switch is turned off, the display and navigation module display (HDD navigation system) records various types of memory and settings. As a result, after turning the power switch off, make sure to wait at least 60 seconds before disconnecting the cable from the negative (-) battery terminal.

Tech Tips

After the repair, clear the DTCs, turn the power switch on (IG), wait for 1 minute or more and check for DTCs.

PROCEDURE


  1. CHECK DTC OUTPUT (HV)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

    4. Read output DTCs Click here.

      Result
      Result Proceed to
      Only U029A-123 is output. A
      DTCs other than U029A-123 are also output. B

    5. Disconnect the intelligent tester from the DLC3.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK HARNESS AND CONNECTOR (IGCT VOLTAGE)

    CAUTION:

    Be sure to wear insulated gloves.


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

    2. Check that the service plug grip is not installed.

      Note

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    3. Remove the No. 1 hybrid vehicle battery carrier bracket sub-assembly Click here.

    4. Connect the cable to the negative (-) battery terminal.

    5. Turn the power switch on (IG).

    6. A01JBYOE03
      Text in Illustration
      *1

      Component with harness connected

      (Battery Smart Unit)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      c1-4 (IGCT) - c1-8 (GND) Power switch on (IG) 11 to 14 V

      Note


      • After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

      • Turning the power switch on (IG) with the service plug grip removed causes an interlock switch system DTC (P0A0D-350) to be set. Use the intelligent tester to clear the DTCs Click here.

    7. Turn the power switch off.

    8. Install the No. 1 hybrid vehicle battery carrier bracket sub-assembly Click here.


    NG

    CHECK BATTERY SMART UNIT POWER SOURCE CIRCUIT (IGCT, GND)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - BATTERY SMART UNIT)

    CAUTION:

    Be sure to wear insulated gloves.


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

    2. Check that the service plug grip is not installed.

      Note

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    3. Disconnect connector L5 from the power management control ECU Click here.

      Note

      Before disconnecting the connector, push in on the connector body to check that the connector is not loose or disconnected.

    4. Remove the No. 1 hybrid vehicle battery carrier bracket sub-assembly Click here.

    5. A01J9DNE11
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)
      *b

      Rear view of wire harness connector

      (to Battery Smart Unit)

      Disconnect connector c1 from the battery smart unit.

      Note


      • Before disconnecting the connector, push in on the connector body to check that the connector is not loose or disconnected.

      • Push in on each connector between the power management control ECU and the battery smart unit to check that each connector is not loose or disconnected.

    6. A01JBNUE04
      Text in Illustration
      *1 Engine Room Junction Block Assembly
      *2 AM2 Fuse
      *3 IGCT NO. 2 Fuse

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L5-32 (BTH+) - c1-2 (BTH+) Power switch off Below 1 Ω
      L5-33 (BTH-) - c1-3 (BTH-) Power switch off Below 1 Ω
      c1-2 (BTH+) - c1-8 (GND) and Body ground Power switch off 10 kΩ or higher
      c1-3 (BTH-) - c1-8 (GND) and Body ground Power switch off 10 kΩ or higher
    7. A01JA6DE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      		 - -

      Remove the IGCT NO. 2 fuse and AM2 fuse from the engine room junction block assembly.

    8. Disconnect all connectors from the power management control ECU.

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

      A01JCSWE05
      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L5-32 (BTH+) - L6-7 (AM21) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - L5-1 (AM22) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - A21-2 (+B2) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - A22-5 (+B1) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - A22-6 (MREL) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - A22-1 (IG2) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - L6-1 (ACCD) Power switch off 10 kΩ or higher
      L5-32 (BTH+) L6-2 (IG1D) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - A22-2 (IG2D) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - A21-4 (FCTL) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - L5-14 (SPDI) Power switch off 10 kΩ or higher
      L5-32 (BTH+) - A21-16 (GI) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - L6-7 (AM21) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - L5-1 (AM22) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - A21-2 (+B2) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - A22-5 (+B1) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - A22-6 (MREL) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - A22-1 (IG2) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - L6-1 (ACCD) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - L6-2 (IG1D) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - A22-2 (IG2D) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - L5-14 (SPDI) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - A21-4 (FCTL) Power switch off 10 kΩ or higher
      L5-33 (BTH-) - A21-16 (GI) Power switch off 10 kΩ or higher

      Note

      When taking a measurement with a tester, do not apply excessive force to the tester probe to avoid damaging the holder.

    10. Connect the cable to the negative (-) battery terminal.

    11. Connect the battery smart unit connector.

    12. Install the No. 1 hybrid vehicle battery carrier bracket sub-assembly Click here.

    13. Connect the power management control ECU connectors Click here.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK POWER MANAGEMENT CONTROL ECU

    CAUTION:

    Be sure to wear insulated gloves.


    1. Check that the service plug grip is not installed.

      Note

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Remove the No. 1 hybrid vehicle battery carrier bracket sub-assembly Click here.

    3. A01J9DNE11

      Disconnect connector c1 from the battery smart unit.

    4. Turn the power switch on (IG).

    5. A01J8G4E03
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Battery Smart Unit)

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

      Note

      Turning the power switch on (IG) with the service plug grip removed causes an interlock switch system DTC to be set. Use the intelligent tester to clear the DTCs Click here.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      c1-2 (BTH+) - c1-8 (GND) Power switch on (IG) 2.3 to 2.7 V
      c1-3 (BTH-) - c1-8 (GND) Power switch on (IG) 2.3 to 2.7 V

    6. Turn the power switch off.

    7. A01J8G4E04
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Battery Smart Unit)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      c1-2 (BTH+) - c1-3 (BTH-) Power switch off 4.4 to 5.4 kΩ

      Tech Tips

      Resistance becomes 2.0 kΩ or less when there is short circuit in the power management control ECU.

    8. Connect the battery smart unit connector.

    9. Install the No. 1 hybrid vehicle battery carrier bracket sub-assembly Click here.


    NG

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    OK

    REPLACE BATTERY SMART UNIT Click here