Toyota Tundra Service Manual: Transponder Chip Malfunction (B2793,B2794,B2797,B2798)

DESCRIPTION

  • DTC B2793 is stored when a malfunction is found in the key during key ID code registration or a key ID code is not registered normally. Replace the key if key ID code registration cannot be performed normally and this DTC is output.
  • DTC B2794 is stored when a key with an incomplete key ID 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 No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2793

Transponder Chip Malfunction

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

  • Transponder key coil
  • Transponder key ECU assembly
  • Insert the key into the ignition key cylinder.

B2794

Unmatched Encryption Code

A key with an incomplete key ID code is inserted into the ignition key cylinder (1 trip detection logic*).

  • Transponder key coil
  • Transponder key ECU assembly
  • Insert the key into the ignition key cylinder.

B2797

Communication Malfunction No. 1

A key with a BCC malfunction is inserted into the ignition key cylinder (1 trip detection logic*).

  • Transponder key coil
  • Transponder key ECU assembly
  • Insert the key into the ignition key cylinder.

B2798

Communication Malfunction No. 2

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

  • Transponder key coil
  • Transponder key ECU assembly
  • Insert the key 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

B2793

Abnormal Status

B2794

Different Encrypt Code

B2797

Bcc Malfunction

B2798

Frame Error

CAUTION / NOTICE / HINT

NOTICE:

  • If the transponder key ECU assembly is replaced, refer to Registration

    Click here

  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Click here

NEXT

2.

CHECK FOR DTC

(a) Insert and remove each registered key one at a time, and check for DTCs each time.

Click here

HINT:

  • Before checking for DTCs, perform "DTC Output Confirmation Operation" procedure.
  • If DTC B2793, B2794, B2797 or B2798 are stored, clear the DTCs before checking the next key.

OK:

DTC B2793, B2974, B2797 or B2798 is not output.

Result

Proceed to

DTCs are not output

A

DTCs are output for all of the keys

B

DTCs are output for any of the keys

C

A

USE SIMULATION METHOD TO CHECK

C

REPLACE KEY THAT DTC IS OUTPUT

B

3.

CHECK CONNECTION OF CONNECTOR

(a) Check that the connectors are properly connected to the transponder key coil.

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

OK:

Engine starts.

OK

END (CONNECTOR WAS NOT CONNECTED PROPERLY)

NG

4.

CHECK TRANSPONDER KEY COIL

(a) Clear the DTCs.

Click here

(b) Replace the transponder key coil.

Click here

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

OK:

Engine starts.

OK

END (TRANSPONDER KEY COIL WAS DEFECTIVE)

NG

REPLACE TRANSPONDER KEY ECU ASSEMBLY

    Antenna Coil Open / Short (B2784)

    Unmatched Key Code (B2795)

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