Engine Immobilizer System (w/o Smart Key System)

THEFT DETERRENT / KEYLESS ENTRY: 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

When the communication line (EFIO-IMI) between the transponder key ECU assembly and ECM is stuck on HI output, the ECM stores this DTC.





* *: Only output while a malfunction is present.

Vehicle Condition and Fail-safe Operation when Malfunction Detected





Related Data List and Active Test





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
* When replacing the transponder key ECU assembly or ECM, refer to Registration How To Proceed With Troubleshooting.
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. CLEAR DTC

(a) Clear the DTCs Engine Immobilizer System (w/o Smart Key System).

NEXT -- Continue to next step.

2. CHECK FOR DTC

(a) Check for DTCs Engine Immobilizer System (w/o Smart Key System).

OK:

DTC B279A is not output.

NG -- CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - ECM)

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

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

(a) Disconnect the C39 transponder key ECU assembly connector.

(b) Disconnect the A35 ECM connector.

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

Standard Resistance:





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

Standard Voltage:





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

4. CHECK TRANSPONDER KEY ECU ASSEMBLY (TERMINAL EFIO)

(a) Using an oscilloscope, check the waveform.





Measurement Condition





HINT
* The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.
* If you forget to note the waveform, etc. and need to recheck it, disconnect and reconnect the ECM connector before rechecking it.

OK:

Waveform is output normally (refer to illustration).

Text in Illustration





Result





B -- REPLACE TRANSPONDER KEY ECU ASSEMBLY

A -- REPLACE ECM Removal

5. REPLACE TRANSPONDER KEY ECU ASSEMBLY

(a) Temporarily replace the transponder key ECU assembly with a new one Removal.

NEXT -- Continue to next step.

6. REGISTER ECU - ECM COMMUNICATION ID

(a) Register the ECU - ECM communication ID Engine Immobilizer System (w/o Smart Key System).

NEXT -- Continue to next step.

7. CHECK WHETHER ENGINE STARTS

(a) Check that the engine starts with the key.

OK:

Engine starts normally.

NG -- REPLACE ECM Removal

OK -- END (TRANSPONDER KEY ECU IS DEFECTIVE)