Last Modified: 05-08-2025 6.11:8.1.0 Doc ID: RM100000001G23B
Model Year Start: 2019 Model: RAV4 Prod Date Range: [11/2018 -           ]
Title: THEFT DETERRENT / KEYLESS ENTRY: IMMOBILISER SYSTEM (for Gasoline Model without Smart Key System): B279A12; Engine Immobiliser System Circuit Short to Battery; 2019 - 2025 MY RAV4 [11/2018 -        ]

DTC

B279A12

Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

If the communication line (IMI - EFIO) between the ECM and transponder key ECU assembly 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

Communication line (EFIO-IMI) between the ECM and transponder key ECU assembly is stuck high.
  • Wire harness or connector
  • ECM
  • Transponder key ECU assembly

DTC Output Confirmation Operation:

  • Turn the ignition switch to ON and wait 6 seconds.

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

Engine cannot be started (initial ignition occurs and engine cranks, then ignition stops)

Engine cannot be started

Related Data List and Active Test

DTC No.

Data List and Active Test

B279A12

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Before replacing the transponder key ECU assembly or ECM, refer to the Registration.

    Click here 2019 - 2022 MY RAV4 [11/2018 - 10/2022]; THEFT DETERRENT / KEYLESS ENTRY: IMMOBILISER SYSTEM (for Gasoline Model without Smart Key System): REGISTRATION 2023 - 2025 MY RAV4 [10/2022 -        ]; THEFT DETERRENT / KEYLESS ENTRY: IMMOBILISER SYSTEM (for Gasoline Model without Smart Key System): REGISTRATION

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

PROCEDURE

1.

CHECK CONNECTION OF CONNECTOR

(a) Turn the ignition switch off.

(b) Check that the connectors are properly connected to the ECM and transponder key ECU assembly.

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

(Transponder Key ECU Assembly)

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

Measurement Condition:

Tester Connection

Condition

Tool Setting

Specified Condition

G52-11 (EFIO) - Body ground

Within 3 seconds of engine start or within 3 seconds of ignition switch turned ON 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

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C

REPLACE ECM 2019 - 2020 MY RAV4 [11/2018 - 08/2020]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 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 - 2025 MY RAV4 [10/2023 -        ]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL

B

3.

CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - ECM)

(a) Disconnect the A24 ECM connector.

(b) Disconnect the G52 transponder key ECU assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G52-11 (EFIO) - A24-26 (IMI)

Always

Below 1 Ω
OK

REPLACE ECM 2019 - 2020 MY RAV4 [11/2018 - 08/2020]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 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 - 2025 MY RAV4 [10/2023 -        ]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR