HYBRID BATTERY SYSTEM, Diagnostic DTC:U029A-123

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

DESCRIPTION

The battery voltage sensor detects the HV battery conditions (voltage, current, and temperature) and the battery cooling fan frequency, and sends the detected signals to the hybrid vehicle control ECU assembly via serial communication. (The hybrid vehicle control ECU assembly does not send signals to the battery voltage sensor.)

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate
U029A-123 Lost Communication with Hybrid Battery Pack Sensor Module

Serial communication error between the hybrid vehicle control ECU assembly and battery voltage sensor: The hybrid vehicle control ECU assembly cannot receive signals from the battery voltage sensor correctly.

(1 trip detection logic)

  • Wire harness or connector

  • Hybrid vehicle control ECU assembly

  • Battery voltage sensor

 Comes on

Master Warning Light:

Comes on

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 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 and perform the following procedure to check that DTCs are not output.


  1. Turn the power switch 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 power switch on (IG).

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

    4. Read output DTCs.


      Powertrain > Hybrid Control > Trouble Codes
      Result
      Result Proceed to
      Only U029A-123 is output. A
      DTCs except U029A-123 are also output. B

    5. Turn the power switch off.

    6. Disconnect the GTS from the DLC3.


    B

    GO TO DTC CHART (HYBRID BATTERY SYSTEM) Click here

    A

  2. CHECK BATTERY VOLTAGE SENSOR (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. Remove the upper No. 5 HV battery carrier bracket.

      Click here

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

    4. Turn the power switch on (IG).

    5. B004GIXC83
      *a

      Component with harness connected

      (Battery Voltage Sensor)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      p1-1 (IGCT) - p1-5 (GND) Power switch on (IG) 11 to 14 V

      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.

      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 upper No. 5 HV battery carrier bracket.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY VOLTAGE SENSOR POWER SOURCE CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - BATTERY VOLTAGE SENSOR)

    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 O141 hybrid vehicle control ECU assembly 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 upper No. 1 hybrid battery cover sub-assembly.

      Click here

    4. Disconnect the p1 battery voltage sensor connector.

      Note

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

    5. B004G8NC22
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU Assembly)
      *b

      Rear view of wire harness connector

      (to Battery Voltage Sensor)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      O141-32 (BTH+) - p1-2 (BTH+) Power switch off Below 1 Ω
      O141-33 (BTH-) - p1-3 (BTH-) Power switch off Below 1 Ω
      p1-2 (BTH+) - p1-5 (GND) and Body ground Power switch off 10 kΩ or higher
      p1-3 (BTH-) - p1-5 (GND) and Body ground Power switch off 10 kΩ or higher

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

    7. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      O141-32 (BTH+) - Body ground Power switch on (IG) Below 1 V
      O141-33 (BTH-) - Body ground Power switch on (IG) Below 1 V

      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.

    9. Turn the power switch off.

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

    11. Reconnect the p1 battery voltage sensor connector.

    12. Install the upper No. 1 hybrid battery cover sub-assembly.

    13. Reconnect the O141 hybrid vehicle control ECU assembly connector.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HYBRID VEHICLE CONTROL ECU ASSEMBLY

    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 upper No. 1 hybrid battery cover sub-assembly.

      Click here

    3. Disconnect the p1 battery voltage sensor connector.

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

    5. Turn the power switch on (IG).

    6. B004G7XC31
      *a

      Rear view of wire harness connector

      (to Battery Voltage Sensor)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      p1-2 (BTH+) - p1-5 (GND) Power switch on (IG) 2.3 to 2.7 V
      p1-3 (BTH-) - p1-5 (GND) Power switch on (IG) 2.3 to 2.7 V

      Note

      If the power switch is turned on (IG) with the connectors disconnected, other DTCs will be stored. Be sure to clear the DTCs after the inspection.

    7. Turn the power 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 Condition Specified Condition
      p1-2 (BTH+) - p1-3 (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 hybrid vehicle control ECU assembly.

    10. Reconnect the p1 battery voltage sensor connector.

    11. Install the upper No. 1 hybrid battery cover sub-assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BATTERY VOLTAGE SENSOR Click here

    NG

    REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY Click here