THEFT DETERRENT / KEYLESS ENTRY: IMMOBILISER SYSTEM (w/o Smart Key System): B279A12; Engine Immobiliser System Circuit Short to Battery; 2018 - 2024 MY Camry [03/2017

Last Modified: 11-20-2023	6.11:8.1.0	Doc ID: RM1000000012VQ2
Model Year Start: 2018	Model: Camry	Prod Date Range: [03/2017 - ]
Title: THEFT DETERRENT / KEYLESS ENTRY: IMMOBILISER SYSTEM (w/o Smart Key System): B279A12; Engine Immobiliser System Circuit Short to Battery; 2018 - 2024 MY Camry [03/2017 - ]

DTC

B279A12

Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

If the communication line (EFIO-IMI) to the transponder key ECU assembly is stuck high (e.g. shorted to +B), the ECM stores 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:

If the transponder key ECU assembly or ECM is replaced, refer to Registration.
Click here
After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.	CHECK CONNECTION OF CONNECTOR

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

OK:

Connectors are properly connected.

CONNECT CONNECTORS PROPERLY

CHECK ECM

(a) Disconnect the K60 transponder key ECU assembly connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
K60-11 (EFIO) - Body ground	Always	11 to 14 V

GO TO STEP 4

3.	CHECK TRANSPONDER KEY ECU ASSEMBLY (TERMINAL EFIO)

(a) Connect the K60 transponder key ECU assembly connector.

(b) Using an oscilloscope, check the waveform.

Component with harness connected

(Transponder Key ECU Assembly)

Waveform

Approximately 160 ms.

Approximately 270 ms.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

K60-11 (EFIO) - Body ground

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

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

Pulse generation

(See waveform)

REPLACE ECM

REPLACE TRANSPONDER KEY ECU ASSEMBLY

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

(a) Disconnect the A24 ECM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
K60-11 (EFIO) - A24-26 (IMI)	Ignition switch ON	Below 1 Ω