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 battery cooling fan voltage, and sends the detected signals to the hybrid vehicle control ECU via serial communication.

DTC No. INF Code DTC Detection Condition Trouble Area
U029A 123

Serial communication error between the hybrid vehicle control ECU and battery smart unit: The hybrid vehicle control ECU cannot receive signals from the battery smart unit correctly.

(1 trip detection logic)

  • Wire harness or connector

  • Hybrid vehicle control ECU

  • Battery smart unit

WIRING DIAGRAM

Refer to the wiring diagram for DTC P0AFC-123 Click here.

CAUTION / NOTICE / HINT

CAUTION:


  • 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

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

Note

After turning the ignition 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.

Tech Tips

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Turn the ignition switch to ON (IG) and wait for 2 minutes or more.

PROCEDURE


  1. CHECK DTC OUTPUT (HYBRID CONTROL)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON (IG).

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

    4. Check and record any HV system DTCs, INF codes and freeze frame data.

    5. Check for DTCs Click here.

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

    6. Turn the ignition switch off.

    7. Disconnect the GTS from the DLC3.


    B

    GO TO DTC CHART (HYBRID BATTERY SYSTEM) 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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Remove the No. 1 hybrid battery exhaust duct Click here.

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

    4. Turn the ignition switch to ON (IG).

    5. A004FT7E02
      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 Switch Condition Specified Condition
      K32-3 (IGCT) - K32-6 (GND) Ignition switch ON (IG) 11 to 14 V

      Note

      Turning the ignition switch to ON (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.

      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)

    6. Turn the ignition switch off.

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

    8. Install the No. 1 hybrid battery exhaust duct.


    NG

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

    OK

  3. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BATTERY SMART UNIT)

    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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Disconnect the hybrid vehicle control ECU connector Click here.

    3. Remove the No. 1 hybrid battery exhaust duct Click here.

    4. Disconnect the battery smart unit connector.

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

      A004G1HE02
      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F55-32 (BTH+) - K32-1 (BTH+) Ignition switch off Below 1 Ω
      F55-33 (BTH-) - K32-4 (BTH-) Ignition switch off Below 1 Ω
      F55-32 (BTH+) - Other terminals and body ground Ignition switch off 10 kΩ or higher
      F55-33 (BTH-) - Other terminals and body ground Ignition switch off 10 kΩ or higher
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)
      *b

      Rear view of wire harness connector

      (to Battery Smart Unit)

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

    7. Turn the ignition switch to ON (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F55-32 (BTH+) - body ground Ignition switch ON (IG) Below 1 V
      F55-33 (BTH-) - body ground Ignition switch ON (IG) Below 1 V

      Note

      Turning the ignition switch to ON (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    9. Turn the ignition switch off.

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

    11. Connect the battery smart unit connector.

    12. Install the No. 1 hybrid battery exhaust duct.

    13. Connect the hybrid vehicle control ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (HYBRID VEHICLE CONTROL ECU- BATTERY SMART UNIT)

    OK

  4. CHECK HYBRID VEHICLE 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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Remove the No. 1 hybrid battery exhaust duct Click here.

    3. Disconnect the battery smart unit connector.

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

    5. Turn the ignition switch to ON (IG).

    6. A004FHKE02
      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.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      K32-1 (BTH+) - K32-6 (GND) Ignition switch ON (IG) 2.3 to 2.7 V
      K32-4 (BTH-) - K32-6 (GND) Ignition switch ON (IG) 2.3 to 2.7 V

      Note

      Turning the ignition switch to ON (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    7. Turn the ignition switch off.

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

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      K32-1 (BTH+) - K32-4 (BTH-) Ignition switch off 4.4 to 5.4 kΩ
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Battery Smart Unit)

      Tech Tips

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

    10. Connect the battery smart unit connector.

    11. Install the No. 1 hybrid battery exhaust duct.


    OK

    REPLACE BATTERY SMART UNIT Click here

    NG

    REPLACE HYBRID VEHICLE CONTROL ECU Click here