Vehicle Interior

Engine Immobiliser System Malfunction (B2799)

~2min read
DESCRIPTION

This DTC is stored when one of the following occurs: 1) the ECM detects errors in its own communications with the transponder key ECU assembly; 2) the ECM detects errors in the communication lines; or 3) the ECU - ECM communication ID between the transponder key ECU assembly and ECM is different and an engine start is attempted. Before troubleshooting for this DTC, make sure no engine immobiliser DTCs are output. If output, troubleshoot the engine immobiliser DTCs first.

DTC Code

DTC Detection Condition

Trouble Area

B2799

One of the following conditions is met:

  • An error in communication between the ECM and transponder key ECU assembly.
  • An error in the communication lines.
  • The ECU - ECM communication ID is different during communication with the transponder key ECU assembly.
  • Harness or connector
  • Transponder key ECU assembly
  • ECM
WIRING DIAGRAM
CAUTION / NOTICE / HINT

NOTICE:

When the transponder key ECU assembly and/or ECM is replaced, refer to Registration (See page ).


PROCEDURE
  1. CLEAR DTC

(a) Clear the DTCs (See page ).


NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC B2799 is not output.


OK

USE SIMULATION METHOD TO CHECK

NG
  1. REREGISTER ECU - ECM COMMUNICATION ID

(a) Reregister the ECU - ECM communication ID (See page ).


NEXT
  1. CLEAR DTC

(a) Clear the DTCs (See page ).


NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC B2799 is not output.


OK

END

NG
  1. CHECK CONNECTION OF CONNECTOR

(a) Turn the ignition switch off.

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

OK:

Connectors are properly connected.


NG

CONNECT CONNECTOR CORRECTLY

OK
  1. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - ECM)

(a) Disconnect the F34 ECU connector.

(b) Disconnect the F50 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F34-13 (EFIO) - F50-14 (IMI)

Always

Below 1 Ω

F34-12 (EFII) - F50-20 (IMO)

F34-13 (EFIO) or F50-14 (IMI) - Body ground

Always

10 kΩ or higher

F34-12 (EFII) or F50-20 (IMO) - Body ground


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
  1. REPLACE TRANSPONDER KEY ECU ASSEMBLY

(a) Temporarily replace the transponder key ECU assembly with a new one (See page ).


NEXT
  1. REREGISTER ECU - ECM COMMUNICATION ID

(a) Reregister the ECU - ECM communication ID (See page ).


NEXT
  1. CLEAR DTC

(a) Clear the DTCs (See page ).


NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC B2799 is not output.


OK

END (TRANSPONDER KEY ECU IS DEFECTIVE)


NG

REPLACE ECM

Test yourself

A quick Toyota 4Runner quiz: every answer comes with an explanation and a link to the manual page.