DTC B2791 Communication Condition Failure between ECM

DESCRIPTION

This DTC is output when the ID code box dose not respond to a verification request signal from the ECM.

If the engine switch is turned off immediately after an engine start, this DTC is also detected.

DTC No.	DTC Detection Condition	Trouble Area
B2791	ID code box dose not respond to a verification request signal from ECM	Wire harness ID code box ECM

Dtc B2791 Communication Condition Failure Between Ecm. ENGINE IMMOBILISER. Lexus IS250 IS220d GSE20 ALE20

1.CHECK DTC OUTPUT

Delete the DTC .

Recheck for DTC .

USE SIMULATION METHOD TO CHECK

A

2.ECU COMMUNICATION ID REGISTRATION

Recheck for DTC .

END

A

3.CHECK HARNESS AND CONNECTOR (ID CODE BOX - ECM)

Disconnect the J69 ECU and A49 ECM connectors.

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

Standard resistance:
Tester Connection Condition Specified Condition
J69-6 (EFIO) - A49-16 (IMI) Always Below 1 Ω
J69-6 (EFIO) - Body ground Always 10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.REPLACE ID CODE BOX

Replace the ID code box.

NEXT

5.KEY REGISTRATION

NEXT

6.ECU COMMUNICATION ID REGISTRATION

NEXT

7.CHECK DTC OUTPUT

Delete the DTC .

Recheck for DTC .

REPLACE ECM

END