Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VJL1
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 -           ]
Title: THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): B2794,B2797,B2798; Unmatched Encryption Code; 2016 - 2020 MY Sienna [12/2015 -        ]

DTC

B2794

Unmatched Encryption Code

DTC

B2797

Communication Malfunction No. 1

DTC

B2798

Communication Malfunction No. 2

DESCRIPTION

  • 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

B2794

A key with an incomplete key code is inserted into the ignition key cylinder.
  • Key
  • Wire harness or connector
  • Transponder key coil
  • Transponder key ECU assembly

B2797

A key with a Bcc malfunction is inserted into the ignition key cylinder.

B2798

Key code identification cannot be completed within the specified time.

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the key and transponder key ECU assembly, refer to the Registration (See page 2016 - 2020 MY Sienna [12/2015 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): REGISTRATION ).
  • After performing repairs, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs (See page 2016 MY Sienna [12/2015 - 08/2016]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): DTC CHECK / CLEAR 2017 - 2020 MY Sienna [08/2016 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): DTC CHECK / CLEAR ).

NEXT

2.

CHECK FOR DTC

(a) Insert and remove each registered key one at a time, and check for DTCs each time (See page 2016 MY Sienna [12/2015 - 08/2016]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): DTC CHECK / CLEAR 2017 - 2020 MY Sienna [08/2016 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): DTC CHECK / CLEAR ).

HINT:

  • Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.
  • If DTC is stored, clear the DTCs before checking the next key.

OK:

DTC B2794, B2797 and B2798 is not output.

Result

Result

Proceed to

OK

A

NG (all keys)

B

NG (any key)

C
A

USE SIMULATION METHOD TO CHECK

(See page 2016 MY Sienna [12/2015 - 08/2016]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2017 MY Sienna [08/2016 - 11/2017]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2018 - 2020 MY Sienna [11/2017 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING )
C

REPLACE KEY THAT CANNOT START ENGINE
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.

REPLACE TRANSPONDER KEY COIL

(a) Clear the DTC (See page 2016 MY Sienna [12/2015 - 08/2016]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): DTC CHECK / CLEAR 2017 - 2020 MY Sienna [08/2016 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): DTC CHECK / CLEAR ).

(b) Replace the transponder key coil (See page 2016 - 2020 MY Sienna [12/2015 -        ]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY AMPLIFIER: REMOVAL ).

(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