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 the serial communication system.

DTC No. DTC Detection Condition Trouble Area
U029A-123 Problem in serial communication between the battery smart unit and power management control ECU (1 trip detection)

  • Wire harness or connector

  • Power management control ECU

  • Battery smart unit

WIRING DIAGRAM

B001KKAE05

CAUTION / NOTICE / HINT

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 set.

  • 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 removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work Click here.

Tech Tips

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

Note

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work Click here.

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 / DTC.

    4. Check for 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 BATTERY SMART UNIT (IGCT VOLTAGE)

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

    3. Turn the power switch on (IG).

    4. B001M5QE02
      Text in Illustration
      *a

      Component with harness connected

      (Battery Smart Unit)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      i1-4 (IGCT) - i1-8 (GND) Power switch on (IG) 11 to 14 V

      Note

      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.

      Tech Tips

      As there might be an intermittent malfunction in the battery smart unit power source circuit, inspect the following even if the measured voltage is as specified:


      • Installation condition of fuse(s) (before removing fuse(s)) (IGCT circuit)

      • Fuse condition (before and after removing fuse(s)) (IGCT circuit)

      • Connection condition of connectors (IGCT circuit)

      • Wire harness condition (IGCT circuit)

      • Wire harness condition (GND circuit)

    5. Turn the power switch off.

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


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY SMART UNIT POWER SOURCE CIRCUIT)

    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 of the auxiliary battery.

    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 H3 from the power management control ECU Click here.

    4. B001N2AE01

      Disconnect connector i1 from the battery smart unit.

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

      B001L0SE01
      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H3-32 (BTH+) - i1-2 (BTH+) Power switch off Below 1 Ω
      H3-33 (BTH-) - i1-3 (BTH-) Power switch off Below 1 Ω
      i1-2 (BTH+) - i1-8 (GND) and Body ground Power switch off 10 kΩ or higher
      i1-3 (BTH-) - i1-8 (GND) and Body ground Power switch off 10 kΩ or higher
      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)
    6. B001MPQE01
      Text in Illustration
      *1 Engine Room Junction Block Assembly
      *2 AM2 Fuse
      *3 IGCT No. 2 Fuse

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

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

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

      B001MMAE04
      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H3-32 (BTH+) - H4-7 (AM21) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - H3-1 (AM22) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - A19-2 (+B2) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - A20-5 (+B1) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - A20-6 (MREL) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - A20-1 (IG2) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - H4-1 (ACCD) Power switch off 10 kΩ or higher
      H3-32 (BTH+) H4-2 (IG1D) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - A20-2 (IG2D) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - A19-4 (FCTL) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - H3-14 (SPDI) Power switch off 10 kΩ or higher
      H3-32 (BTH+) - A19-16 (GI) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - H4-7 (AM21) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - H3-1 (AM22) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - A19-2 (+B2) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - A20-5 (+B1) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - A20-6 (MREL) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - A20-1 (IG2) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - H4-1 (ACCD) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - H4-2 (IG1D) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - A20-2 (IG2D) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - H3-14 (SPDI) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - A19-4 (FCTL) Power switch off 10 kΩ or higher
      H3-33 (BTH-) - A19-16 (GI) Power switch off 10 kΩ or higher
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      		 - -

      Note

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

    9. Connect the cable to the negative (-) battery terminal of the auxiliary battery.

    10. Connect the battery smart unit connector.

    11. 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. B001N2AE01

      Disconnect connector i1 from the battery smart unit.

    3. Turn the power switch on (IG).

    4. B001L4EE03
      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
      i1-2 (BTH+) - i1-8 (GND) Power switch on (IG) 2.3 to 2.7 V
      i1-3 (BTH-) - i1-8 (GND) Power switch on (IG) 2.3 to 2.7 V

    5. Turn the power switch off.

    6. B001LCDE03
      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
      i1-2 (BTH+) - i1-3 (BTH-) Power switch off 4.4 to 5.4 kΩ

      Tech Tips

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

    7. Connect the battery smart unit connector.


    OK

    REPLACE BATTERY SMART UNIT Click here

    NG

    REPLACE POWER MANAGEMENT CONTROL ECU Click here