Engine Immobiliser W/O Smart Key

ENGINE IMMOBILISER: ENGINE IMMOBILISER SYSTEM (w/o Smart Key System): B279A: Theft Deterrent System Communication Line High Fixation
B279A - Theft Deterrent System Communication Line High Fixation

DESCRIPTION

If the communication line (EFIO-IMI) to the transponder key ECU is stuck on HI output, the ECM outputs this DTC.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CLEAR DTC

(a) Clear the DTC Engine Immobiliser System (w/o Smart Key System).

NEXT -- Continue to next step.

2. CHECK FOR DTC

(a) Check for DTC Engine Immobiliser System (w/o Smart Key System).

Result





HINT
If any DTCs other than B279A are output, troubleshoot those DTCs first.

B -- GO TO DIAGNOSTIC TROUBLE CODE CHART Engine Immobiliser System (w/o Smart Key System)
A -- Continue to next step.

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





(a) Disconnect the E46 ECU connector.

(b) Disconnect the A9 ECM connector.

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

Standard Resistance:

for 2AR-FE
for 2GR-FE










Standard Voltage:

for 2AR-FE
for 2GR-FE










NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK TRANSPONDER KEY ECU (OUTPUT)

(a) Measure waveform.





Waveform 1 (Reference)





OK:

Waveform is output normally (see illustration).

Result





C -- CHECK TRANSPONDER KEY ECU (POWER SOURCE AND BODY GROUND)

B -- REPLACE ECM Removal

A -- REPLACE ECM Removal

5. CHECK TRANSPONDER KEY ECU (POWER SOURCE AND BODY GROUND)

(a) Turn the ignition switch ON.





(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE TRANSPONDER KEY ECU Removal