HYBRID BATTERY SYSTEM, Diagnostic DTC:U029A-123

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

DESCRIPTION

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

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

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

(1 trip detection logic)

  • EV control ECU

  • Battery voltage sensor

  • Wire harness or connector

Master Warning Light:

Comes on

WIRING DIAGRAM

B000ZGLE01

CAUTION / NOTICE / HINT

CAUTION:


  • B006JFB
    B006JM4

    Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grips from both FC stack assembly and EV battery.


    • Inspecting the high-voltage system

    • Disconnecting the low voltage connector of the inverter with converter assembly

    • Disconnecting the low voltage connector of the EV battery

    • Disconnecting the low voltage connector of the FC stack assembly

    • Disconnecting the low voltage connector of the FC converter assembly

      Tech Tips

      No removal order is specified for the service plug grips of the FC stack assembly and EV battery.

  • B006JBZ

    After removing the service plug grip from the EV battery, 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 grip from the FC stack assembly, store it in a safe location and use the "HIGH-VOLTAGE, DO NOT TOUCH" sign to notify other technicians that you are working on the high-voltage system.

  • B000ZMTC04
    *a Without waiting for 10 minutes

    After removal of the service plug grips of both FC stack assembly and EV battery, wait for at least 10 minutes before touching the high-voltage connectors and 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 are necessary to discharge the high-voltage capacitors inside the inverter with converter assembly and FC stack 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

  • When reinstalling the service plug grip to the FC stack assembly or the EV battery, slide the lever of the service plug until the letters "UNLOCK" are completely hidden, and insert it firmly.

    Click here

  • When the vehicle is parked with the power switch off, if the FC control ECU judges that the FC stack temperature will go below 0°C (32°F), it activates the FC air compressor, hydrogen pump and FC cooling water pump for a maximum of 180 seconds and drains water from the FC stack assembly. When performing inspection or repairs with the power switch off (not on (IG) or on (READY)), disconnect the cable from the negative (-) auxiliary battery terminal before performing work (If the auxiliary battery voltage is needed to conduct inspection, warm up the FC system beforehand).

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 (EV)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Enter the following menus: Powertrain / EV / Trouble Codes.

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

    5. Read output DTCs.


      Powertrain > EV > Trouble Codes
      Result
      Result Proceed to
      Only U029A-123 is output. A
      DTCs other than U029A-123 are also output. B

    6. Turn the power switch off.

    7. 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 to FC stack assembly and EV battery.

      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 rear seatback assembly.

      Click here

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

    4. Turn the power switch on (IG).

    5. B000ZL3C35
      *a

      Component with harness connected

      (Battery Voltage Sensor)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      P29-3 (IGCT) - P29-6 (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.

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

      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 power switch off.

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

    8. Install the rear seatback assembly.

      Result
      Proceed to
      OK
      NG

    NG

    CHECK FUSE (BATT VL SSR) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (EV CONTROL ECU - BATTERY VOLTAGE SENSOR)

    CAUTION:

    Be sure to wear insulated gloves.


    1. Check that the service plug grip is not installed to FC stack assembly and EV battery.

      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 EV control ECU connector.

      Note

      Before disconnecting the connector, check that it is not loose or disconnected.

    3. Remove the rear seatback assembly.

      Click here

    4. Disconnect the battery voltage sensor connector.

      Note


      • Before disconnecting the connector, check that it is not loose or disconnected.

      • Check that each connector between the EV control ECU and battery voltage sensor is not loose or disconnected.

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

      B000ZQ8C03
      *a

      Rear view of wire harness connector

      (to EV Control ECU)

      		 *b

      Rear view of wire harness connector

      (to Battery Voltage Sensor)
      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      G45-32 (BTH+) - P29-1 (BTH+) Power switch off Below 1 Ω
      G45-33 (BTH-) - P29-4 (BTH-) Power switch off Below 1 Ω
      P29-1 (BTH+) - P29-6 (GND) and Body ground Power switch off 10 kΩ or higher
      P29-4 (BTH-) - P29-6 (GND) and Body ground 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.

    6. B000ZKFC05
      *1 Motor Compartment Relay Block
      *2 MPX-B fuse
      *3 IG2 NO. 2 fuse
      *4 PM-IGCT fuse

      Remove the PM-IGCT fuse, MPX-B fuse and IG2 NO. 2 fuse from the motor compartment relay block.

    7. Disconnect the A28, A27, G45 and G46 EV control ECU connectors.

    8. B000ZGDC08
      *a

      Rear view of wire harness connector

      (to EV Control ECU)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      G45-32 (BTH+) - G46-3 (BATT) Power switch off 10 kΩ or higher
      G45-32 (BTH+) - A28-1 (+B2) Power switch off 10 kΩ or higher
      G45-32 (BTH+) - A27-4 (+B1) Power switch off 10 kΩ or higher
      G45-32 (BTH+) - A27-6 (MREL) Power switch off 10 kΩ or higher
      G45-32 (BTH+) - A28-3 (IG2) Power switch off 10 kΩ or higher
      G45-33 (BTH-) - G46-3 (BATT) Power switch off 10 kΩ or higher
      G45-33 (BTH-) - A28-1 (+B2) Power switch off 10 kΩ or higher
      G45-33 (BTH-) - A27-4 (+B1) Power switch off 10 kΩ or higher
      G45-33 (BTH-) - A27-6 (MREL) Power switch off 10 kΩ or higher
      G45-33 (BTH-) - A28-3 (IG2) 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.

    9. Reconnect the EV control ECU connector.

    10. Install the PM-IGCT fuse, MPX-B fuse and IG2 NO. 2 fuse to the motor compartment relay block.

    11. Reconnect the battery voltage sensor connector.

    12. Install the rear seatback assembly.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK EV CONTROL ECU

    CAUTION:

    Be sure to wear insulated gloves.


    1. Check that the service plug grip is not installed to FC stack assembly and EV battery.

      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 rear seatback assembly.

      Click here

    3. Disconnect the battery voltage sensor connector.

      Note

      Before disconnecting the connector, check that it is not loose or disconnected.

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

    5. Turn the power switch on (IG).

    6. B000ZUTC04
      *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 Switch Condition Specified Condition
      P29-1 (BTH+) - P29-6 (GND) Power switch on (IG) 2.3 to 2.7 V
      P29-4 (BTH-) - P29-6 (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.

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

    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 Switch Condition Specified Condition
      P29-1 (BTH+) - P29-4 (BTH-) Power switch off 4.4 to 5.4 kΩ

      Note

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

      Tech Tips

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

    10. Reconnect the battery voltage sensor connector.

    11. Install the rear seatback assembly.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BATTERY VOLTAGE SENSOR Click here

    NG

    REPLACE EV CONTROL ECU Click here

  5. CHECK FUSE (BATT VL SSR)


    1. Remove the BATT VL SSR fuse from the motor compartment relay block.

    2. B000ZH3C01
      *1 Motor Compartment Relay Block
      *2 BATT VL SSR Fuse

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      BATT VL SSR fuse Always Below 1 Ω

      Note

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

    3. Install the BATT VL SSR fuse to the motor compartment relay block.

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY VOLTAGE SENSOR - IGCT NO. 1 RELAY)

    NG

    REPLACE FUSE (BATT VL SSR)