Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: 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 cannot be performed normally and this DTC is output.
  • DTC B2794 is stored when a key with an incomplete key code is inserted into the ignition key cylinder.
  • DTC B2797 is stored when a key with a BCC malfunction is inserted into the ignition key cylinder.
  • DTC B2798 is stored when a key is inserted into the ignition key cylinder but a communication error occurs between the key and transponder key ECU assembly.

DTC Code

DTC Detection Condition

Trouble Area

DTC Output Confirmation Operation

B2793

A transponder chip malfunction (1 trip detection logic*).

  • Key
  • Transponder key coil
  • Transponder key ECU assembly

Insert the key into the ignition key cylinder, turn the ignition switch from off to ON and wait at least 20 seconds.

B2794

A key with an incomplete key ID code is used to turn the ignition switch to ON (1 trip detection logic*).

B2797

A key with a BCC malfunction is used to turn the ignition switch to ON (1 trip detection logic*).

B2798

Key ID code identification cannot be completed within the specified time (1 trip detection logic*).

  • *: 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

B2793

-

B2794

-

B2797

-

B2798

-

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs (See page ).

NEXT

2.

CHECK DTC OUTPUT

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

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

HINT:

If DTC B2793, B2794, B2797, or B2798 is stored, clear the DTCs before checking the next key.

OK:

DTC B2793, B2974, B2797 and B2798 are not output.

Result

Result

Proceed to

DTCs are output for all of the keys

A

DTCs are output for any of the keys

B

DTCs are not output

C

B

REPLACE KEY THAT DTC IS OUTPUT

C

USE SIMULATION METHOD TO CHECK

A

3.

CHECK CONNECTION OF CONNECTOR

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

(b) Check that the engine starts with the key.

OK:

Engine starts normally.

OK

END (CONNECTOR WAS NOT CONNECTED PROPERLY)

NG

4.

REPLACE TRANSPONDER KEY COIL

(a) Clear the DTCs (See page (b) Replace the transponder key coil (See page ).

(b) Replace the transponder key coil (See page (c) Check that the engine starts with the key (See page ).

(c) Check that the engine starts with the key (See page OK: ).

OK:

Engine starts normally.

OK

END (TRANSPONDER KEY COIL WAS DEFECTIVE)

NG

REPLACE TRANSPONDER KEY ECU ASSEMBLY

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 D ...

Engine does not Start because No Initial Combustion
DESCRIPTION When a key is inserted into the ignition key cylinder, the transponder key coil receives the key ID code and sends it to the transponder key ECU assembly. If an error i ...

Other materials:

On-vehicle Inspection
ON-VEHICLE INSPECTION PROCEDURE 1. CONNECT TECHSTREAM (a) Warm up the engine. (b) Turn the ignition switch to off. (c) Connect the Techstream to the DLC3. (d) Turn the ignition switch to ON. (e) Turn the Techstream on. (f) Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test. 2. ...

Transmission Range Sensor Circuit Malfunction (PRNDL Input) (P0705)
DESCRIPTION The park/neutral position switch detects the shift lever position and sends signals to the ECM. DTC No. DTC Detection Condition Trouble Area P0705 One of the following conditions is met: (A) Any 2 or more of the followin ...

Removal
REMOVAL PROCEDURE 1. REMOVE FRONT WIPER ARM HEAD CAP (a) Using a screwdriver with its tip wrapped in protective tape, disengage the 3 claws to remove the front wiper arm head cap. Text in Illustration *a Protective Tape HINT ...

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