Toyota Tacoma 2015-2018 Service Manual: Theft Deterrent System Communication Line High Fixation (B279A,B279A12)

Toyota Tacoma 2015-2018 Service Manual / Engine Immobiliser / Engine Immobiliser System(w/o Smart Key System) / Theft Deterrent System Communication Line High Fixation (B279A,B279A12)

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.	DTC Detection Condition	Trouble Area	DTC Output Confirmation Operation
B279A*1	Communication line (EFIO-IMI) between the ECM and transponder key ECU assembly is stuck high.	Wire harness or connector ECM Transponder key ECU assembly	Turn the ignition switch to ON and wait 6 seconds.
B279A12*2	Communication line (EFIO-IMI) between the ECM and transponder key ECU assembly is stuck high.	Wire harness or connector ECM Transponder key ECU assembly	Turn the ignition switch to ON and wait 6 seconds.

*1: for 2TR-FE
*2: for 2GR-FKS

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
B279A*1	-
B279A12*1	-

*1: for 2TR-FE
*2: for 2GR-FKS

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

CLEAR DTC

(a) Clear the DTCs (See page ).

2.	CHECK DTC OUTPUT

(a) Perform "DTC Output Confirmation Operation" procedure.

(b) Check for DTCs (See page Result ).

Result

Result	Proceed to
DTC B279A (for 2TR-FE) or B279A12 (for 2GR-FKS) is output	A
DTC B279A (for 2TR-FE) or B279A12 (for 2GR-FKS) is not output	B

USE SIMULATION METHOD TO CHECK

3.	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

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

(a) Disconnect the T10 transponder key ECU assembly connector.

(b) Disconnect the E14*1 or E20*2 ECM connector.

*1: for 2GR-FKS
*2: for 2TR-FE

Standard Resistance:

Tester Connection	Condition	Specified Condition
T10-13 (EFIO) - E14-8 (IMI)*1	Always	Below 1 Ω
T10-13 (EFIO) or E14-8 (IMI) - Body ground*1	Always	10 kΩ or higher
T10-13 (EFIO) - E20-10 (IMI)*2	Always	Below 1 Ω
T10-13 (EFIO) or E20-10 (IMI) - Body ground*2	Always	10 kΩ or higher

*1: for 2GR-FKS
*2: for 2TR-FE

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	REPLACE TRANSPONDER KEY ECU ASSEMBLY

(a) Replace the transponder key ECU assembly with a new one (See page ).

CLEAR DTC

(a) Clear the DTCs (See page ).

7.	CHECK FOR DTC

(a) Perform "DTC Output Confirmation Operation" procedure.

(b) Check for DTCs (See page Result ).

Result

Result	Proceed to
DTC B279A (for 2TR-FE) or B279A12 (for 2GR-FKS) is not output	A
DTC B279A is output (for 2TR-FE)	B
DTC B279A12 is output (for 2GR-FKS)	C

END (TRANSPONDER KEY ECU ASSEMBLY WAS DEFECTIVE)

REPLACE ECM

Diagnostic Trouble Code Chart

DIAGNOSTIC TROUBLE CODE CHART HINT: If a trouble code is stored during the DTC check, inspect the trouble areas listed for that code. For details of the code, refer to "See page" below. ...

Theft Deterrent System Presence Detection (B279C,B279C95)

DESCRIPTION If an ECM that is incompatible with the engine immobiliser system is installed, the ECM stores this DTC. DTC No. DTC Detection Condition Trouble Area ...

Other materials:

Cruise Control Switch Circuit
DESCRIPTION This circuit sends signals to the ECM depending on the cruise control main switch condition. The battery supplies the positive (+) battery voltage to the cruise control main switch. Then terminal CCS of the ECM receives the voltage as the signal according to the switch condition. ...

Dtc Check / Clear
DTC CHECK / CLEAR 1. DTC CHECK USING TECHSTREAM (a) Connect the Techstream to the DLC3. (b) Turn the ignition switch to ON. (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Air Conditioner / Trouble Codes. (e) Check for DTCs. 2. DTC CLEAR USING TECHSTREAM (a) Conn ...

Skid Control Buzzer Circuit (C1A4A)
DESCRIPTION Based on dynamic radar cruise control system operation, the forward recognition camera provides warnings to the driver by sounding the skid control buzzer. DTC C1A4A is stored when a malfunction is detected in the skid control buzzer circuit. DTC No. Detectio ...