B278A

DOOR LOCK: SMART KEY SYSTEM: B278A: Short to GND in Immobiliser System Power Source Circuit

DTC B278A - Short to GND in Immobiliser System Power Source Circuit

DESCRIPTION

- Operating the engine switch starts the engine or changes the power source status (ACC / IG / OFF / START).
- The engine switch is a momentary type switch which turns on only while the switch is held down. The certification ECU always stores the power source status (OFF / ACC / ON). If the battery has been removed and reinstalled, the power source status maintained before removal is restored.
- The transponder amplifier is built into the engine switch.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK WIRE HARNESS (CERTIFICATION ECU - ENGINE SWITCH)




(a) Disconnect the D39 ECU connector.




(b) Disconnect the D21 switch connector.
(c) Measure the resistance according to the value(s) in the table below.
Resistance:






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

2. REPLACE ENGINE SWITCH (RECONFIRM DTC)
(a) Replace the engine switch.
(b) Clear the DTC and repeat the procedure to re-check it Reading and Clearing Diagnostic Trouble Codes.
OK:
DTC is not output.
OK -- END (ENGINE SWITCH IS DEFECTIVE)

NG -- REPLACE CERTIFICATION ECU