B278A

ENGINE IMMOBILISER: 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 output when the engine switch power source supply line is open or shorted.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
If the certification ECU is replaced, register the key and ECU communication ID Engine Immobiliser System (W/ Smart Key System).

PROCEDURE

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

(a) Disconnect the E58 ECU and E52 switch connectors.





(b) 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 HARNESS AND CONNECTOR (ENGINE SWITCH POWER SOURCE)

(a) Reconnect the E58 ECU and E52 switch connectors.





(b) 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.

3. CHECK HARNESS AND CONNECTOR (ENGINE SWITCH BODY GROUND)

(a) 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.

4. CHECK ENGINE SWITCH

(a) After replacing the engine switch Removal with a normal one, check that the engine starts.

OK:

The engine starts.

NG -- REPLACE CERTIFICATION ECU

OK -- END