Last Modified: 05-08-2025 6.11:8.1.0 Doc ID: RM100000001G23A
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): B279986; Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid; 2019 - 2025 MY RAV4 [11/2018 -        ]

DTC

B279986

Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid

DESCRIPTION

If there is a communication malfunction between the ECM and transponder key ECU assembly, or when the communication ID codes do not match, the ECM stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B279986

Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid

One of the following conditions is met:

  • Error in communication between ECM and transponder key ECU assembly.
  • Error in communication lines.
  • Communication ID is different during communication between ECM and transponder key ECU assembly.
  • Wire harness or connector
  • Transponder key ECU assembly
  • ECM

DTC Output Confirmation Operation:

  • Start the engine and wait 10 seconds.
  • After disconnecting and reconnecting the cable to the negative (-) battery terminal, turn the ignition switch to ON and wait 10 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

-

Related Data List and Active Test

DTC No.

Data List and Active Test

B279986

-

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".

HINT:

If transponder key ECU assembly DTCs are output simultaneously, troubleshoot the transponder key ECU assembly DTCs first.

PROCEDURE

1.

REGISTER ECU COMMUNICATION ID

(a) Reregister the ECU communication ID.

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

NEXT

2.

CHECK ECM (TERMINAL EFII)

(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

G52-10 (EFII) - 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

Normal waveform

A

Terminal EFII stuck low (2.4 V or less)

B

Waveform length or shape is abnormal, or EFII terminal stuck at Hi (12 V)

C
B

GO TO STEP 6

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

A

3.

CHECK TRANSPONDER KEY ECU ASSEMBLY (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)
NG

REPLACE TRANSPONDER KEY ECU ASSEMBLY 2019 MY RAV4 RAV4 HV [11/2018 - 02/2019]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2019 MY RAV4 RAV4 HV [02/2019 - 10/2019]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2020 MY RAV4 RAV4 HV [10/2019 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2021 MY RAV4 RAV4 HV [08/2020 - 12/2021]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2022 MY RAV4 RAV4 HV [12/2021 - 10/2022]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2023 MY RAV4 RAV4 HV [10/2022 - 10/2023]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2024 - 2025 MY RAV4 RAV4 HV [10/2023 -        ]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL

OK

4.

REGISTER ECU COMMUNICATION ID

(a) Reregister the ECU communication ID.

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

NEXT

5.

CHECK WHETHER ENGINE STARTS

(a) Check that the engine starts.

Result

Proceed to

Engine was started

A

Engine was not started

B
A

END (ECU COMMUNICATION ID HAS NOT BEEN REGISTERED)
B

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

6.

CHECK ECM (TERMINAL IMO)

(a) Disconnect the ECM connector.

*a

Front view of wire harness connector

(to ECM)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A24-25 (IMO) - Body ground

Ignition switch turned ON using registered electrical key transmitter sub-assembly

Terminal IMO stuck low (2.4 V or less)

Terminal IMO stuck high (12 V)

Result

Proceed to

Terminal IMO stuck low (2.4 V or less)

A

Terminal IMO stuck high (12 V)

B
B

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

A

7.

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

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G52-10 (EFII) - A24-25 (IMO)

Always

Below 1 Ω

G52-10 (EFII) or A24-25 (IMO) - Other terminals and body ground

Always

10 kΩ or higher
OK

REPLACE TRANSPONDER KEY ECU ASSEMBLY 2019 MY RAV4 RAV4 HV [11/2018 - 02/2019]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2019 MY RAV4 RAV4 HV [02/2019 - 10/2019]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2020 MY RAV4 RAV4 HV [10/2019 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2021 MY RAV4 RAV4 HV [08/2020 - 12/2021]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2022 MY RAV4 RAV4 HV [12/2021 - 10/2022]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2023 MY RAV4 RAV4 HV [10/2022 - 10/2023]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL 2024 - 2025 MY RAV4 RAV4 HV [10/2023 -        ]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR