Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001B4EO
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: A25A-FXS (ENGINE CONTROL): SFI SYSTEM: U029387; Lost Communication With Hybrid Powertrain Control Module Missing Message; 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

U029387

Lost Communication With Hybrid Powertrain Control Module Missing Message

MONITOR DESCRIPTION

The ECM and hybrid vehicle control ECU assembly send and receive signals via CAN communication.

If a communication error occurs between the ECM and hybrid vehicle control ECU assembly, the ECM illuminates the MIL and stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

U029387

Lost Communication With Hybrid Powertrain Control Module Missing Message

All of the following conditions are met for 0.576 seconds or more (1 trip detection logic):

  • Power switch on (IG)
  • Auxiliary battery voltage is 10 V or higher
  • No communication between ECM and hybrid vehicle control ECU assembly
  • CAN communication system
  • Hybrid vehicle control ECU assembly
  • ECM

Comes on

DTC stored

SAE Code: U0293

MONITOR STRATEGY

Related DTCs

U0293: Lost communication with hybrid control module

Required Sensors/Components (Main)

ECM

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.576 seconds

MIL Operation

Immediate

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

None

Both of the following conditions are met

-

Auxiliary battery voltage

10 V or higher

Power switch

On (IG)

TYPICAL MALFUNCTION THRESHOLDS

Communication signal

Lost communication with hybrid control module

CONFIRMATION DRIVING PATTERN

HINT:

  • 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 2019 - 2022 MY Avalon HV [04/2018 -        ]; A25A-FXS (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR

  • When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

    Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; A25A-FXS (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR

  1. Connect the Techstream to the DLC3.
  2. Turn the power switch on (IG).
  3. Turn the Techstream on.
  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  5. Turn the power switch off and wait for at least 30 seconds.
  6. Turn the power switch on (IG) [A].
  7. Turn the Techstream on.
  8. Wait 5 seconds or more.
  9. Enter the following menus: Powertrain / Engine / Trouble Codes [B].
  10. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
  12. Input the DTC: U029387.
  13. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL
    • DTC judgment completed
    • System normal

    ABNORMAL
    • DTC judgment completed
    • System abnormal

    INCOMPLETE
    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system is malfunctioning.
    • [A] to [B]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the auxiliary battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

CAUTION / NOTICE / HINT

NOTICE:

  • Vehicle Control History may be stored in the hybrid vehicle control ECU assembly if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the freeze frame data and Vehicle Control History can be useful for troubleshooting.

    Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): VEHICLE CONTROL HISTORY 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): VEHICLE CONTROL HISTORY

    (Select Powertrain in Health Check and then check the time stamp data.)

    Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; A25A-FXS (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR

  • If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU assembly, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.

    Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): VEHICLE CONTROL HISTORY 2021 - 2022 MY Avalon HV [08/2020 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY): VEHICLE CONTROL HISTORY

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

GO TO CAN COMMUNICATION SYSTEM

(a) Refer to the CAN Communication System.

Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM (for HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

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