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. INF Code 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

A005BRLE03

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 stored.

  • Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. 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.

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 (HYBRID CONTROL)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

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

    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. Turn the power switch off.


    B

    GO TO DTC CHART (HYBRID BATTERY SYSTEM) Click here

    A

  2. CHECK HARNESS AND CONNECTOR (B AND IGCT VOLTAGE)

    Note

    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 battery shield sub-assembly Click here.

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

    4. Turn the power switch on (IG).

      Note

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

    5. A005D41E02
      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
      L144-1 (B) - L144-4 (GND) Power switch off 8.6 V or more
      L144-5 (IGCT) - L144-4 (GND) Power switch on (IG) 8.6 V or more

      Tech Tips

      As there might be an intermittent malfunction in the battery voltage sensor 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 power switch off.

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

    8. Install the No. 1 hybrid battery shield sub-assembly.


    NG

    CHECK POWER SOURCE CIRCUIT (BATTERY VOLTAGE SENSOR)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT 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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Disconnect the L5 power management control ECU connector.

      Note

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

    3. Remove the No. 1 hybrid battery shield sub-assembly Click here.

    4. A005AZIE02

      Disconnect the L144 battery smart unit connector.

      Note

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

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

      A005DJJE01
      Standard Resistance
      Tester Connection Condition Specified Condition
      L5-32 (BTH+) - L144-2 (BTH+) Power switch off Below 1 Ω
      L5-33 (BTH-) - L144-3 (BTH-) Power switch off Below 1 Ω
      L144-4 (GND) - Body ground Power switch off Below 1 Ω
      L144-2 (BTH+) - L144-4 (GND) and Body ground Power switch off 10 kΩ or higher
      L144-3 (BTH-) - L144-4 (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. A005AQCE01
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 AM2 Fuse
      *3 HV BATT Fuse
      *4 IGCT No. 2 Fuse

      Remove the IGCT No. 2 fuse, HV BATT fuse and AM2 fuse from the engine room relay block and junction block assembly.

    7. Disconnect the A21, A22, L5 and L6 power management control ECU connectors.

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

      A005EZUE02
      Standard Resistance
      Tester Connection 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
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      		 - -

    9. Install the IGCT No. 2 fuse, HV BATT fuse and AM2 fuse.

    10. Reconnect the A21, A22, L5 and L6 power management control ECU connectors.

    11. Reconnect the L144 battery smart unit connector.

    12. Install the No. 1 hybrid battery shield sub-assembly.


    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 battery shield sub-assembly Click here.

    3. A005AIKE02

      Disconnect the L144 battery smart unit connector.

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

    5. Turn the power switch on (IG).

      Note

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

    6. A005CU4E02
      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 Condition Specified Condition
      L144-2 (BTH+) - L144-4 (GND) Power switch on (IG) 2.3 to 2.7 V
      L144-3 (BTH-) - L144-4 (GND) Power switch on (IG) 2.3 to 2.7 V

    7. Turn the power switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L144-2 (BTH+) - L144-3 (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.

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

    10. Reconnect the L144 battery smart unit connector.

    11. Install the No. 1 hybrid battery shield sub-assembly.


    OK

    REPLACE BATTERY SMART UNIT Click here

    NG

    REPLACE POWER MANAGEMENT CONTROL ECU Click here