B279A

THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILIZER 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 (immobilizer code ECU) is stuck high output (e. g. shorted to +B), the ECM stores this DTC.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
If the ID code box (immobilizer code ECU) is replaced, register the ECU code and ECU communication ID Engine Immobilizer System.

PROCEDURE

1. CHECK DTC OUTPUT

(a) Clear the DTCs Engine Immobilizer System.

(b) Recheck for DTCs Engine Immobilizer System.

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

Result:





B -- GO TO DIAGNOSTIC TROUBLE CODE CHART Engine Immobilizer System
A -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILIZER CODE ECU) - ECM)

(a) Disconnect the ID code box (immobilizer code ECU) connector.

(b) Disconnect the ECM connector.





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

Standard Resistance:





Standard Voltage:





Text in Illustration





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

3. CHECK ID CODE BOX (IMMOBILIZER CODE ECU) (OUTPUT)

(a) Reconnect the ID code box (immobilizer code ECU) connector.

(b) Reconnect the ECM connector.





(c) Using an oscilloscope, check the waveform.

Waveform (Reference):





OK:

Waveform is output normally (see illustration).

Result:





Text in Illustration





C -- REPLACE ECM Removal

B -- REPLACE ECM Removal
A -- Continue to next step.

4. REPLACE ID CODE BOX (IMMOBILIZER CODE ECU)

(a) Replace the ID code box (immobilizer code ECU) Removal.

NEXT -- Continue to next step.

5. REGISTER ECU CODE

(a) Register the ECU code Engine Immobilizer System.

NEXT -- Continue to next step.

6. REGISTER ECU COMMUNICATION ID

(a) Register the ECU communication ID Engine Immobilizer System.

NEXT -- Continue to next step.

7. CHECK DTC OUTPUT

(a) Clear the DTCs Engine Immobilizer System.

(b) Recheck for DTCs Engine Immobilizer System.

OK:

DTC B279A is not output.

Result:





C -- REPLACE ECM Removal

B -- REPLACE ECM Removal

A -- END (ID CODE BOX (IMMOBILIZER CODE ECU) WAS DEFECTIVE)