Toyota Tacoma (2015-2018) Service Manual: Antenna Coil Open / Short (B2784)

Toyota Tacoma (2015-2018) Service Manual / Engine Immobiliser / Engine Immobiliser System(w/o Smart Key System) / Antenna Coil Open / Short (B2784)

DESCRIPTION

When an open or short circuit is detected in the antenna coil built into the transponder key coil, the transponder key ECU assembly stores this DTC.

DTC No.	DTC Detection Condition	Trouble Area	DTC Output Confirmation Operation
B2784	The antenna coil in the transponder key coil is open/shorted.	Wire harness or connector Transponder key coil Transponder key ECU assembly	Insert the door control transmitter assembly into the ignition key cylinder, turn the ignition switch from off to ON and wait at least 20 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
B2784	Antenna Coil Status

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

If the transponder key ECU assembly 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 FOR DTC

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

(b) Check for DTCs (See page OK: ).

OK:

DTC B2784 is not output.

Result

Result	Proceed to
DTC B2784 is output	A
DTC B2784 is not output	B

USE SIMULATION METHOD TO CHECK

3.	CHECK CONNECTION OF CONNECTOR

(a) Check that the connector is properly connected to the transponder key coil.

CLEAR DTC

(a) Clear the DTCs (See page ).

5.	CHECK FOR DTC

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

(b) Check for DTCs. (See page OK: ).

OK:

DTC B2784 is not output.

Result

Result	Proceed to
DTC B2784 is not output	A
DTC B2784 is output	B

END (CONNECTOR WAS NOT CONNECTED PROPERLY)

6.	CHECK TRANSPONDER KEY COIL (OUTPUT)

(a) Using an oscilloscope, check the waveform.

Text in Illustration

Component with harness connected

(Transponder Key Coil)

Waveform 1

Waveform 2

Measurement Condition:

Tester Connection	Condition	Tool Setting	Specified Condition
T9-1 (ANT1) - Body ground	Within 3 seconds of inserting door control transmitter assembly into ignition key cylinder	2 V/DIV., 500 ms./DIV.	Pulse generation (See waveform 1)
T9-5 (ANT2) - Body ground	Within 3 seconds of inserting door control transmitter assembly into ignition key cylinder	2 V/DIV., 500 ms./DIV.	Pulse generation (See waveform 2)

Tester Connection

Condition

Tool Setting

Specified Condition

T9-1 (ANT1) - Body ground

Within 3 seconds of inserting door control transmitter assembly into ignition key cylinder

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

Pulse generation

(See waveform 1)

T9-5 (ANT2) - Body ground

Within 3 seconds of inserting door control transmitter assembly into ignition key cylinder

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

Pulse generation

(See waveform 2)

OK:

Waveform is similar to that shown in the illustration.

Result

Result	Proceed to
NG	A
OK	B

REPLACE TRANSPONDER KEY COIL

7.	CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - TRANSPONDER KEY COIL)

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

(b) Disconnect the T9 transponder key coil connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
T10-4 (ANT1) - T9-1 (ANT1)	Always	Below 1 Ω
T10-15 (ANT2) - T9-5 (ANT2)	Always	Below 1 Ω
T10-4 (ANT1) or T9-1 (ANT1) - Body ground	Always	10 kΩ or higher
T10-15 (ANT2) or T9-5 (ANT2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.	REPLACE TRANSPONDER KEY ECU ASSEMBLY

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

NOTICE:

Key ID code registration is necessary when replacing the transponder key ECU assembly, refer to Registration (See page ).

CLEAR DTC

(a) Clear the DTCs (See page ).

10.	CHECK FOR DTC

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

(b) Check for DTCs (See page OK: ).

OK:

DTC B2784 is not output.

Result

Result	Proceed to
DTC B2784 is not output	A
DTC B2784 is output	B

END (TRANSPONDER KEY ECU ASSEMBLY WAS DEFECTIVE)

REPLACE TRANSPONDER KEY COIL

Push Switch / Key Unlock Warning Switch Malfunction (B2780)

DESCRIPTION This DTC is stored if the transponder key ECU assembly does not detect that the unlock warning switch assembly is ON even when the key is in the ignition key cylinder. Under normal co ...

Transponder Chip Malfunction (B2793,B2794,B2797,B2798)

DESCRIPTION DTC B2793 is stored when a malfunction is found in the key during key code registration or a key code is not registered normally. Replace the key if key code registration c ...

Other materials:

Open in Stop Light Switch Circuit (C1425)
DESCRIPTION The skid control ECU (brake actuator assembly) detects the brake operating conditions through a signal transmitted by the stop light switch. The skid control ECU incorporates a circuit to detect an open circuit. This DTC is output when an open circuit is detected in the stop light ...

Removal
REMOVAL PROCEDURE 1. REMOVE FRONT WHEEL 2. INSPECT FRONT SUSPENSION LOWER ARM (a) Install the hub nuts onto the disc. (b) Using a dial indicator, check the lower ball joint for excessive play when you push the hub nuts up and down with a force of 294 N (30 kgf, 66 lbf). Maximum: 0.5 mm ( ...

Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter
DESCRIPTION for Audio Function: The radio and display receiver assembly receives a vehicle speed signal from the combination meter assembly and sends the signal to radio and display receiver assembly. for Automatic Sound Levelizer (ASL): This circuit is necessary fo ...