Last Modified: 11-20-2023 6.11:8.1.0 Doc ID: RM1000000014TL6
Model Year Start: 2018 Model: Camry Prod Date Range: [06/2017 - 08/2022]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function): B279A12; Engine Immobiliser System Circuit Short to Battery; 2018 - 2022 MY Camry [06/2017 - 08/2022]

DTC

B279A12

Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

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

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

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 2018 - 2022 MY Camry [03/2017 - 08/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function): HOW TO PROCEED WITH TROUBLESHOOTING

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

    Click here 2018 - 2019 MY Camry [03/2017 - 09/2019]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function): REGISTRATION 2020 - 2022 MY Camry [09/2019 - 08/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function): REGISTRATION

  • After performing repairs, 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 certification ECU (smart key ECU assembly).

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY
OK

2.

CHECK WHETHER ENGINE STARTS

(a) Check that the engine starts.

OK:

Engine starts normally.

OK

USE SIMULATION METHOD TO CHECK 2018 MY Camry [06/2017 - 08/2018]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2019 MY Camry [08/2018 - 09/2019]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2020 MY Camry [09/2019 - 03/2020]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2020 MY Camry [03/2020 - 10/2020]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2021 MY Camry [10/2020 - 08/2021]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2022 - 2024 MY Camry [08/2021 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING

NG

3.

CHECK ECM

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A13-4 (EFIO) - Body ground

Engine switch on (IG)

11 to 14 V

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))
NG

GO TO STEP 5

OK

4.

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

(a) Connect the A13 certification ECU (smart key ECU assembly) connector.

(b) 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.

Measurement Condition:

Tester Connection

Condition

Tool Setting

Specified Condition

A13-4 (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)
OK

REPLACE ECM

for A25A-FKS: Click here 2018 - 2020 MY Camry [06/2017 - 03/2020]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2020 MY Camry [03/2020 - 10/2020]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2021 - 2022 MY Camry [10/2020 - 08/2022]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL

for 2GR-FKS: Click here 2018 - 2020 MY Camry [06/2017 - 10/2020]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL 2021 - 2022 MY Camry [10/2020 - 08/2022]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 2018 - 2020 MY Camry [06/2017 - 10/2020]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2021 - 2024 MY Camry [10/2020 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL

5.

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

(a) Disconnect the A24*1 or A21*2 ECM connector.

  • *1: for A25A-FKS
  • *2: for 2GR-FKS

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

Standard Resistance:

for A25A-FKS

Tester Connection

Condition

Specified Condition

A13-4 (EFIO) - A24-26 (IMI)

Always

Below 1 Ω

for 2GR-FKS

Tester Connection

Condition

Specified Condition

A13-4 (EFIO) - A21-59 (IMI)

Always

Below 1 Ω
OK

REPLACE ECM

for A25A-FKS: Click here 2018 - 2020 MY Camry [06/2017 - 03/2020]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2020 MY Camry [03/2020 - 10/2020]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL 2021 - 2022 MY Camry [10/2020 - 08/2022]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL

for 2GR-FKS: Click here 2018 - 2020 MY Camry [06/2017 - 10/2020]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL 2021 - 2022 MY Camry [10/2020 - 08/2022]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR