Toyota Tundra. Manual — part 369

Fig. 16: Identifying J18 Switch Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

6. CHECK HARNESS AND CONNECTOR (UNLOCK WARNING SWITCH - TRANSPONDER

KEY ECU)

a. Disconnect the J18 switch connector.

b. Disconnect the J26 ECU connector.

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

Standard resistance

HARNESS AND CONNECTOR (UNLOCK WARNING SWITCH - TRANSPONDER KEY
ECU) TESTER CONNECTION SPECIFIED CONDITION CHART

Fig. 17: Checking Harness And Connector (Unlock Warning Switch - Transponder Key
ECU)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Tester Connection

Condition Specified Condition

J26-3(KSW) - J18-1

Always

Below 1 ohms

J26-3(KSW) or J18-1 - Body ground Always

10 kohms or higher

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra

OK: REPLACE TRANSPONDER KEY ECU (see REMOVAL )

DTC B2784 ANTENNA COIL OPEN / SHORT

DESCRIPTION

The antenna coil receives key code signals from the transponder chip in the key grip. The coil is built into the
transponder key amplifier, which amplifies the key code signals and outputs the signals to the transponder key
ECU.

This DTC is output when there is an open or short malfunction in the antenna coil.

DTC B2784 ANTENNA COIL OPEN / SHORT DETECTION CONDITION CHART

WIRING DIAGRAM

Fig. 18: Antenna Coil Open / Short - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

DTC Code

DTC Detection Condition

Trouble Area

B2784

Antenna coil is open/shorted



Harness or connector



Transponder key ECU



Transponder key amplifier

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra

HINT:

When the transponder key ECU is replaced, reregister the ECU - ECM communication ID (see
REGISTRATION).

1. CLEAR DTC

a. Clear the DTC (see DTC CHECK/CLEAR ).

2. CHECK FOR DTC

a. Check for DTC (see DTC CHECK/CLEAR ).

OK: DTC B2784 is not output.

NG: Go to step 3

OK: USE SIMULATION METHOD TO CHECK (See HOW TO PROCEED WITH
TROUBLESHOOTING )

3. READ VALUE OF TECHSTREAM (ANTENNA COIL)

a. Use the Data List to check if the transponder key coil is functioning properly.

DATA LIST - IMMOBILIZER

OK: NORMAL (Antenna coil is normal) appears on the screen.

NG: Go to step 4

OK: REPLACE TRANSPONDER KEY ECU (see REMOVAL )

4. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - TRANSPONDER KEY

AMPLIFIER)

a. Disconnect the J26 ECU connector.

b. Disconnect the J20 amplifier connector.

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

Standard resistance

HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - TRANSPONDER KEY
AMPLIFIER) TESTER CONNECTION SPECIFIED CONDITION CHART

Tester

Display

Measurement Item/Display

Normal Condition

Diagnostic

Note

Antenna Coil

Antenna coil condition / Normal

or Fail

Normal: Antenna coil is normal
Fail: Antenna coil is
malfunctioning

-

Tester Connection

Condition Specified Condition

J26-14(VC5) - J20-1 (VC5)

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra

Fig. 19: Checking Harness And Connector (Transponder Key ECU - Transponder Key
Amplifier)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

5. REPLACE TRANSPONDER KEY AMPLIFIER

a. Temporarily replace the transponder key amplifier with a new or normally functioning one (see

REMOVAL ).

6. CLEAR DTC

J26-15(CODE) - J20-4 (CODE)

Always

Below 1 ohms

J26-4 (TXCT) - J20-5 (TXCT)

J26-5 (AGND) - J20-7 (AGND)

-,J26-14(VC5) or J20-1 (VC5) - Body ground

Always

10 kohms or higher

J26-15(CODE) or J20-4 (CODE) - Body ground

J26-4 (TXCT) or J20-5 (TXCT) - Body ground

J26-5 (AGND) or J20-7 (AGND) - Body ground

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra