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 transponder key ECU is stuck on HI output, the ECM outputs this DTC.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
* If the transponder key ECU assembly is replaced, register the key and ECU communication ID Programming and Relearning.
* If the ECM is replaced, register the ECU communication ID Programming and Relearning.

PROCEDURE

1. CLEAR DTC

(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

NEXT -- Continue to next step.

2. CHECK DTC OUTPUT

(a) Recheck for DTCs Reading and Clearing Diagnostic Trouble Codes.

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

Result:

A -- GO TO DTC CHART Engine Immobilizer System
B -- Continue to next step.

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

(a) Disconnect the transponder key ECU assembly connector.

(b) Disconnect the ECM connector.

Standard Voltage:

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

4. INSPECT TRANSPONDER KEY ECU ASSEMBLY (OUTPUT)

(a) Reconnect the transponder key ECU assembly connector.

(b) Reconnect the ECM connector.

(c) Measure the waveform.

(1) Measure the waveform.

Waveform 1 (Reference)

*1: for 2AZ-FE
*2: for 2ZR-FE

OK:

Waveform is output normally (see illustration).

Result:

B -- REPLACE ECM Removal

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

5. REPLACE TRANSPONDER KEY ECU ASSEMBLY

(a) Replace the transponder key ECU assembly Removal.

NEXT -- Continue to next step.

6. KEY REGISTRATION

(a) Register the key Programming and Relearning.

NEXT -- Continue to next step.

7. ECU COMMUNICATION ID REGISTRATION

(a) Register the ECU communication ID Programming and Relearning

NEXT -- Continue to next step.

8. CHECK DTC OUTPUT

(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(b) Recheck for DTCs.

OK:

B279A output does not reoccur.

Result:

B -- REPLACE ECM Removal

A -- REPLACE ECM Removal

C -- END (TRANSPONDER KEY ECU IS DEFECTIVE)