Last Modified: 01-30-2024 6.11:8.1.0 Doc ID: RM1000000021J40
Model Year Start: 2022 Model: RAV4 Prod Date Range: [12/2021 -           ]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): B279A12; Engine Immobiliser System Circuit Short to Battery; 2022 - 2024 MY RAV4 [12/2021 -        ]

DTC

B279A12

Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

If the communication line (IMI - EFIO) between the ECM and ID code box (immobiliser code ECU) is stuck high, the ECM 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 ECM and ID code box (immobiliser code ECU) is stuck high (1 trip detection logic*).
  • Harness or connector
  • ID code box (immobiliser code ECU)
  • ECM

DTC output confirmation operation:

  • Turn the engine 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

Engine cannot be started

Engine 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 engine 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) 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) after confirming that the communication systems are functioning properly.

    Click here 2022 - 2023 MY RAV4 [12/2021 - 10/2023]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING 2024 MY RAV4 [10/2023 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING

  • Before replacing the ECM, ID code box (immobiliser code ECU), refer to the Registration.

    Click here 2022 - 2024 MY RAV4 [12/2021 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

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

HINT:

When DTC B279A12 and a 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 engine switch off.

(b) Check that the connectors are properly connected to the ECM and ID code box (immobiliser code ECU).

OK:

Connectors are properly connected.

Result

Proceed to

The connectors are properly connected

A

The connectors are not properly connected

B
B

CONNECT CONNECTORS PROPERLY
A

2.

CHECK ECM (TERMINAL EFIO)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(ID Code Box (Immobiliser Code ECU))

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

Measurement Condition:

Tester Connection

Condition

Tool Setting

Specified Condition

G57-4 (EFIO) - Body ground

Within 3 seconds of engine start or within 3 seconds of engine switch turned on (IG) after cable disconnected and reconnected to battery

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

Pulse generation

(See waveform)

Result

Proceed to

11 to 14 V

A

Below 1 V

B

Normal waveform

C
A

REPLACE ID CODE BOX (IMMOBILISER CODE ECU) 2022 MY RAV4 RAV4 HV [12/2021 - 10/2022]; THEFT DETERRENT / KEYLESS ENTRY: ID CODE BOX: REMOVAL 2023 MY RAV4 RAV4 HV [10/2022 - 10/2023]; THEFT DETERRENT / KEYLESS ENTRY: ID CODE BOX: REMOVAL 2024 MY RAV4 RAV4 HV [10/2023 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ID CODE BOX: REMOVAL

C

REPLACE ECM 2021 - 2022 MY RAV4 [08/2020 - 10/2022]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2023 MY RAV4 [10/2022 - 10/2023]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2024 MY RAV4 [10/2023 -        ]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL

B

3.

CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - ECM)

(a) Disconnect the A24 ECM connector.

(b) Disconnect the G57 ID code box (immobiliser code ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G57-4 (EFIO) - A24-26 (IMI)

Always

Below 1 Ω
OK

REPLACE ECM 2021 - 2022 MY RAV4 [08/2020 - 10/2022]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2023 MY RAV4 [10/2022 - 10/2023]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2024 MY RAV4 [10/2023 -        ]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR