Toyota Tundra. Manual — part 368

2. ECM DTC CHART

HINT:

The DTCs for the engine immobilizer system are specified above. If other codes are output, check the
DTC chart for the SFI system.

ECM

ECM DTC CHART

DTC B2780 PUSH SWITCH / KEY UNLOCK WARNING SWITCH MALFUNCTION

DESCRIPTION

This DTC will be output if the transponder key ECU does not detect that the unlock warning switch is ON even



Harness or connector

B2784

Antenna Coil Open / Short



Transponder key ECU



Transponder key amplifier



Harness or connector

B2793

Transponder Chip Malfunction

Key

B2794

Unmatched Encryption Code

Key

B2795

Unmatched Key Code

Key

B2796

No Communication in Immobilizer
System



Transponder key ECU-Key



Harness or connector



Transponder key amplifier

B2797

Communication Malfunction No. 1



Key



Harness or connector



Transponder key ECU



Transponder key amplifier

B2798

Communication Malfunction No. 2 Key

DTC Code

Detection Item

Trouble Area

B2799

Engine Immobilizer System
Malfunction



Harness or connector



Transponder key ECU



ECM

B279A

Theft Deterrent System
Communication Line High
Fixation



Harness or connector



Transponder key ECU



ECM

B279C

Theft Deterrent System Presence
Detection

ECM

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra

when the ignition switch is ON. Under normal conditions, the unlock warning switch is ON when the ignition
switch is ON.

DTC B2780 PUSH SWITCH / KEY UNLOCK WARNING SWITCH MALFUNCTION DETECTION
CONDITION CHART

WIRING DIAGRAM

Fig. 14: Push Switch / Key Unlock Warning Switch - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

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 B2780 is not output.

NG: Go to step 3

DTC

Code

DTC Detection Condition

Trouble Area

B2780

Unlock warning switch ON is not detected when the ignition
switch is ON.



Transponder key
ECU



Unlock warning
switch



Harness or connector

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra

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

3. READ VALUE OF TECHSTREAM (UNLOCK WARNING SWITCH)

a. Use the Data List to check if the unlock warning switch is functioning properly.

DATA LIST - IMMOBILIZER

OK: ON (key is in ignition key cylinder) appears on the screen.

NG: Go to step 4

OK: REPLACE TRANSPONDER KEY ECU (see REMOVAL )

4. INSPECT UNLOCK WARNING SWITCH

a. Remove the unlock warning switch (See REMOVAL ).

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

Standard resistance

WARNING SWITCH TESTER CONNECTION SPECIFIED CONDITION CHART

Tester

Display

Measurement Item/Range

Normal Condition

Diagnostic

Note

Key SW

Unlock warning switch signal / ON

or OFF

ON: Key is in ignition key
cylinder
OFF: No key is in ignition key
cylinder

-

Tester Connection Switch Condition Specified Condition

1 - 2

Switch is pushed

Below 1 ohms

Switch is not pushed 10 kohms or higher

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra

Fig. 15: Identifying Unlock Warning Switch Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPLACE UNLOCK WARNING SWITCH (See REMOVAL )

OK: Go to Next Step

5. CHECK HARNESS AND CONNECTOR (UNLOCK WARNING SWITCH - BODY GROUND)

a. Disconnect the J18 switch connector.

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

Standard resistance

HARNESS AND CONNECTOR (UNLOCK WARNING SWITCH - BODY GROUND)
TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection Condition Specified Condition

J18-2 - Body ground Always

Below 1 ohms

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Engine Immobilizer - Tundra