HYBRID CONTROL SYSTEM, Diagnostic DTC:U029A87

DTC Code DTC Name
U029A87 Lost Communication with Hybrid/EV Battery Sensor Module Missing Message

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 via serial communication. (The hybrid vehicle control ECU does not send signals to the battery voltage sensor.)

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate
U029A87 Lost Communication with Hybrid/EV Battery Sensor Module Missing Message

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

(1 trip detection logic)

  • Hybrid vehicle control ECU

  • Battery voltage sensor

  • Wire harness or connector

 Comes on

Master Warning Light:

Comes on

CONFIRMATION DRIVING PATTERN

Tech Tips

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

Click here


  1. Connect the GTS to the DLC3.

  2. Turn the power switch on (IG) and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the power switch off and wait for 2 minutes or more.

  5. Turn the power switch on (IG) and turn the GTS on.

  6. With power switch on (IG) and wait for 2 minutes or more.

  7. Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.

  8. Check the DTC judgment result.

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform driving pattern again.

WIRING DIAGRAM

Refer to the wiring diagram for DTC P0AFC00.

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

    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.

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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 and record any HV system DTCs and freeze frame data. Check for DTCs.


      Powertrain > Hybrid Control > Trouble Codes
      Result
      Result Proceed to
      Only U029A87 is output A
      Other than above B

    5. Turn the power switch off.


    B

    GO TO DTC CHART (HYBRID CONTROL 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 No. 1 hybrid battery exhaust duct.

      Tech Tips

      Click here

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

    4. Turn the power switch on (IG).

    5. B004PINC23
      *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
      M35-1 (IGCT) - M35-5 (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 No. 1 hybrid battery exhaust duct.

      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 - 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 F2 hybrid vehicle control ECU connector.

      Note


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

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

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

      Tech Tips

      Click here

    4. Disconnect the M35 battery voltage sensor connector.

      Note


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

      • Check the terminals of the connector for deformation and corrosion.

    5. B004P1IC05
      *a

      Front view of wire harness connector

      (to Hybrid Vehicle Control ECU)
      *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
      F2-41 (BTH+) - M35-2 (BTH+) Power switch off Below 1 Ω
      F2-42 (BTH-) - M35-3 (BTH-) Power switch off Below 1 Ω
      M35-2 (BTH+) - Other terminals and body ground Power switch off 10 kΩ or higher
      M35-3 (BTH-) - Other terminals and body ground Power switch off 10 kΩ or higher

      Note

      Make sure that each connector between the battery voltage sensor and hybrid vehicle control ECU is not loose or disconnected and its terminals are not deformed or corroded.

    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
      F2-41 (BTH+) - Body ground Power switch on (IG) Below 1 V
      F2-42 (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.

      • 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.

    9. Turn the power switch off.

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

    11. Reconnect the M35 battery voltage sensor connector.

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

    13. Reconnect the F2 hybrid vehicle control ECU connector.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

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

      Tech Tips

      Click here

    3. Disconnect the M35 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. B004PSJC05
      *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
      M35-2 (BTH+) - M35-5 (GND) Power switch on (IG) 2.3 to 2.7 V
      M35-3 (BTH-) - M35-5 (GND) Power switch on (IG) 2.3 to 2.7 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.

      • 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
      M35-2 (BTH+) - M35-3 (BTH-) Power switch off 4.4 to 5.4 kΩ

      Tech Tips

      The resistance will be 2.0 kΩ or less if there is an internal short in the hybrid vehicle control ECU.

    10. Reconnect the M35 battery voltage sensor connector.

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

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BATTERY VOLTAGE SENSOR Click here

    NG

    REPLACE HYBRID VEHICLE CONTROL ECU Click here