Toyota Tacoma (2015-2018) Service Manual: Push Switch / Key Unlock Warning Switch Malfunction (B2780)

Toyota Tacoma (2015-2018) Service Manual / Engine Immobiliser / Engine Immobiliser System(w/o Smart Key System) / 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 conditions, the unlock warning switch assembly is ON when the key is in the ignition key cylinder.

DTC No.	DTC Detection Condition	Trouble Area	DTC Output Confirmation Operation
B2780	The unlock warning switch assembly is not detected as being on when the ignition switch is ON (1 trip detection logic*).	Wire harness or connector Unlock warning switch assembly Transponder key ECU assembly	Insert the door control transmitter assembly into the ignition key cylinder.

*: Only output while a malfunction is present.

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
B2780	Key SW

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 B2780 is not output.

Result

Result	Proceed to
DTC B2780 is output	A
DTC B2780 is not output	B

USE SIMULATION METHOD TO CHECK

3.	INSPECT UNLOCK WARNING SWITCH ASSEMBLY

(a) Remove the unlock warning switch assembly (See page (b) Inspect the unlock warning switch assembly (See page ).

(b) Inspect the unlock warning switch assembly (See page ).

REPLACE UNLOCK WARNING SWITCH ASSEMBLY

4.	CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - UNLOCK WARNING SWITCH ASSEMBLY - BODY GROUND)

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

(b) Disconnect the U1 unlock warning switch assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
T10-3 (KSW) - U1-1	Always	Below 1 Ω
T10-3 (KSW) or U1-1 - Body ground	Always	10 kΩ or higher
U1-2 - Body ground	Always	Below 1 Ω

REPLACE TRANSPONDER KEY ECU ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

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Antenna Coil Open / Short (B2784)

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