Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000ZMV5
Model Year Start: 2017 Model: Sienna Prod Date Range: [08/2016 -           ]
Title: THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): B279A12; Engine Immobiliser System Circuit Short to Battery; 2017 - 2020 MY Sienna [08/2016 -        ]

DTC

B279A12

Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

When the communication line (IMI - EFIO) between the ECM and transponder key ECU assembly is stuck on HI output, the ECM stores this DTC.

DTC Code

DTC Detection Condition

Trouble Area

B279A12

The communication line (IMI - EFIO) between the ECM and transponder key ECU assembly is stuck on HI output.
  • Wire harness or connector
  • Transponder key ECU assembly
  • ECM

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the 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 ).
  • When replacing the ECM, refer to the INITIALIZATION (See page 2017 MY Sienna [08/2016 - 11/2017]; 2GR-FKS (ENGINE CONTROL): SFI SYSTEM: INITIALIZATION 2018 - 2020 MY Sienna [11/2017 -        ]; 2GR-FKS (ENGINE CONTROL): SFI SYSTEM: INITIALIZATION ).
  • 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 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) Check for DTCs (See page 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.

OK:

DTC B279A12 is not output.

OK

USE SIMULATION METHOD TO CHECK

(See page 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 )
NG

3.

CHECK CONNECTION OF CONNECTOR

(a) Check that the connectors are properly connected to the ECM and transponder key ECU assembly.

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY
OK

4.

CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - ECM)

(a) Disconnect the D151 transponder key ECU assembly connector.

(b) Disconnect the A69 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D151-13 (EFIO) - A69-59 (IMI)

Always

Below 1 Ω

D151-13 (EFIO) or A69-59 (IMI) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

REPLACE TRANSPONDER KEY ECU ASSEMBLY

(a) Replace the transponder key ECU assembly with a new one (See page 2016 - 2020 MY Sienna [12/2015 -        ]; THEFT DETERRENT / KEYLESS ENTRY: TRANSPONDER KEY ECU: REMOVAL ).

NEXT

6.

REGISTER KEY

(a) Register the key (See page 2016 - 2020 MY Sienna [12/2015 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): REGISTRATION ).

NEXT

7.

REGISTER ECU COMMUNICATION ID

(a) Register the ECU communication ID (See page 2016 - 2020 MY Sienna [12/2015 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/o Smart Key System): REGISTRATION ).

NEXT

8.

CHECK WHETHER ENGINE STARTS

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

OK:

Engine starts normally.

OK

END (TRANSPONDER KEY ECU ASSEMBLY WAS DEFECTIVE)
NG

REPLACE ECM