B279A

ENGINE IMMOBILISER: ENGINE IMMOBILISER SYSTEM: B279A: Theft Deterrent System Communication Line High Fixation

DTC 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 Reading and Clearing Diagnostic Trouble Codes
NEXT -- Continue to next step.

2. CHECK FOR DTC
(a) Check for DTC Reading and Clearing Diagnostic Trouble Codes

Result





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

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

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




(a) Disconnect the T8 ECU and E7 ECM connectors.
(b) 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 TRANSPONDER KEY ECU ASSEMBLY (OUTPUT)




(a) Reconnect the T8 ECU connectors.
(b) Measure the waveform.
Waveform (Reference):





OK:
Waveform is output normally (see illustration).

NG -- CHECK TRANSPONDER KEY ECU ASSEMBLY (POWER SOURCE)
OK -- REPLACE ECM
5. CHECK TRANSPONDER KEY ECU ASSEMBLY (POWER SOURCE)




(a) Turn the ignition switch to 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 ASSEMBLY