Last Modified: 01-30-2024 6.11:8.1.0 Doc ID: RM100000001G228
Model Year Start: 2019 Model: RAV4 Prod Date Range: [11/2018 - 08/2020]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): B279A12; Engine Immobiliser System Circuit Short to Battery; 2019 - 2020 MY RAV4 [11/2018 - 08/2020]

DTC

B279A12

Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

w/o Occupant Classification System:

  • 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.

w/ Occupant Classification System:

  • If the communication line (IMI - EFIO) between the ECM and certification ECU (smart 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

w/o Occupant Classification System:

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

w/ Occupant Classification System:

  • The communication line (IMI - EFIO) between the ECM and certification ECU (smart key ECU assembly) is stuck high (1 trip detection logic*).

w/o Occupant Classification System

  • Harness or connector
  • ID code box (immobiliser code ECU)
  • ECM

w/ Occupant Classification System

  • Harness or connector
  • Certification ECU (smart key ECU assembly)
  • 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

w/o Occupant Classification System:
w/ Occupant Classification System:

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 2019 - 2020 MY RAV4 [11/2018 - 08/2020]; 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)*1 or certification ECU (smart key ECU assembly)*2, refer to the Registration.

    Click here 2019 MY RAV4 [11/2018 - 10/2019]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION 2020 MY RAV4 [10/2019 - 08/2020]; 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".
    • *1: w/o Occupant Classification System
    • *2: w/ Occupant Classification System

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 VEHICLE TYPE

(a) Check vehicle condition.

w/ Occupant Classification System

GO TO STEP 5

w/o Occupant Classification System

2.

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

3.

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) 2019 MY RAV4 RAV4 HV [11/2018 - 02/2019]; THEFT DETERRENT / KEYLESS ENTRY: ID CODE BOX: REMOVAL 2019 MY RAV4 RAV4 HV [02/2019 - 10/2019]; THEFT DETERRENT / KEYLESS ENTRY: ID CODE BOX: REMOVAL 2020 MY RAV4 RAV4 HV [10/2019 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: ID CODE BOX: REMOVAL

C

REPLACE ECM

B

4.

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

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.

CHECK CONNECTION OF CONNECTOR

(a) Turn the engine switch off.

(b) Check that the connectors are properly connected to the ECM and certification ECU (smart 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

6.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (TERMINAL EFIO)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

*b

Waveform

*c

Approximately 160 ms.

*d

Approximately 270 ms.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

A15-4 (EFIO) - Body ground

Engine switch turned on (IG) using registered electrical key transmitter sub-assembly

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 CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 2019 MY RAV4 RAV4 HV [11/2018 - 02/2019]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2019 MY RAV4 RAV4 HV [02/2019 - 10/2019]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2020 MY RAV4 RAV4 HV [10/2019 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL

C

REPLACE ECM

B

7.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ECM)

(a) Disconnect the A24 ECM connector.

(b) Disconnect the A15 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A15-4 (EFIO) - A24-26 (IMI)

Always

Below 1 Ω
OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR