B278A

THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM (w/ Smart Key System): B278A: Short to GND in Immobiliser System Power Source Circuit
B278A - Short to GND in Immobiliser System Power Source Circuit

DESCRIPTION

This DTC is stored when the engine switch power source supply line is open or shorted.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Before replacing the certification ECU, refer to Registration Engine Immobilizer System (w/ Smart Key System).

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ENGINE SWITCH)

(a) Disconnect the F79 ECU connector.

(b) Disconnect the F71 switch connector.

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

Standard Resistance:





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

2. CHECK CERTIFICATION ECU

(a) Using an oscilloscope, check the waveform.





Measurement Condition





OK:

Waveform is output normally (refer to illustration).

Text in Illustration





NG -- REPLACE CERTIFICATION ECU Removal

OK -- REPLACE ENGINE SWITCH Removal