B279A

THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER 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 ID code box (immobiliser code ECU) is stuck on HI output, the ECM outputs this DTC.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CLEAR DTC

(a) Clear the DTCs Engine Immobiliser System.

NEXT -- Continue to next step.

2. CHECK FOR DTC

(a) Check for DTCs Engine Immobiliser System.

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

Result





B -- Go to DIAGNOSTIC TROUBLE CODE CHART Engine Immobiliser System
A -- Continue to next step.

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

(a) Disconnect the E28 box connector.





(b) Disconnect the A38 ECM connector.

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

Standard Resistance:





Standard Voltage:





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

4. CHECK ID CODE BOX (IMMOBILISER CODE ECU) (OUTPUT)





(a) Using an oscilloscope, check the waveform.

Measurement Condition





OK:

Waveform is output normally (See illustration).

NG -- CHECK ID CODE BOX (POWER SOURCE AND BODY GROUND)

OK -- REPLACE ECM Removal

5. CHECK ID CODE BOX (POWER SOURCE AND BODY GROUND)





(a) Turn the engine switch on (IG).

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

Standard Voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ID CODE BOX (IMMOBILISER CODE ECU) Removal