Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001B2OG
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): B279A12; Engine Immobiliser System Circuit Short to Battery; 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

B279A12

Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

If the communication line (IMI - EFIO) between the hybrid vehicle control ECU and certification ECU (smart key ECU assembly) is stuck high, the hybrid vehicle control ECU will store this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B279A12

Engine Immobiliser System Circuit Short to Battery

The communication line (IMI - EFIO) between the hybrid vehicle control ECU and certification ECU (smart key ECU assembly) is stuck high. (1 trip detection logic*)
  • Certification ECU (smart key ECU assembly)
  • Hybrid vehicle control ECU
  • Wire harness or connector

DTC output confirmation operation:

  • Turn the power switch on (IG) and wait 6 seconds.
  • *: Only output while a malfunction is present.

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

Hybrid control system cannot be started

Hybrid control system cannot be started

Related Data List and Active Test

DTC No.

Data List and Active Test

B279A12

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When using the Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
  • The smart key system (for Start Function, HV Model) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Start Function, HV Model) after confirming that the communication systems are functioning properly.

    Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

  • Before replacing the hybrid vehicle control ECU or certification ECU (smart key ECU assembly), refer to Registration.

    Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION 2021 - 2022 MY Avalon HV [08/2020 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION

  • After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

HINT:

When DTC B279A12 and the certification ECU (smart key ECU assembly) DTC are output simultaneously, first perform troubleshooting for the certification ECU (smart key ECU assembly) DTC.

PROCEDURE

1.

CHECK CONNECTION OF CONNECTOR

(a) Turn the power switch off.

(b) Check that the connectors are properly connected to the hybrid vehicle control ECU and certification ECU (smart key ECU assembly).

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY
OK

2.

CHECK WHETHER HYBRID CONTROL SYSTEM STARTS

(a) Check that the hybrid control system starts.

OK:

Hybrid control system starts normally.

OK

USE SIMULATION METHOD TO CHECK

NG

3.

CHECK HYBRID VEHICLE CONTROL ECU

(a) Disconnect the A10 certification ECU (smart key ECU assembly) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A10-4 (EFIO) - Body ground

Power switch off

11 to 14 V → 1 V or less

*a

Front view of wire harness connector

(to Certification ECU (Smart Key ECU Assembly))
NG

GO TO STEP 5

OK

4.

CHECK HYBRID VEHICLE CONTROL ECU (TERMINAL IMI)

(a) Connect the A10 certification ECU (smart key ECU assembly) connector.

(b) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Hybrid Vehicle Control ECU)

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

G47-22 (IMI) - Body ground

Within 3 seconds of hybrid control system start or within 3 seconds of power switch turned on (IG) after cable disconnected and reconnected to auxiliary battery

2 V/DIV., 500 ms./DIV.

Pulse generation

(See waveform)
OK

REPLACE HYBRID VEHICLE CONTROL ECU 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL 2022 MY Avalon HV [08/2021 -        ]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL

5.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - HYBRID VEHICLE CONTROL ECU)

(a) Disconnect the G47 hybrid vehicle control ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A10-4 (EFIO) - G47-22 (IMI)

Always

Below 1 Ω
OK

REPLACE HYBRID VEHICLE CONTROL ECU 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL 2022 MY Avalon HV [08/2021 -        ]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR