B278A

ENGINE IMMOBILIZER: ENGINE IMMOBILIZER SYSTEM: B278A: Short to GND in Immobilizer System Power Source Circuit

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

DESCRIPTION

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






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: If the certification ECU is replaced, register the key and ECU communication ID .

PROCEDURE

1. CHECK DTC OUTPUT
(a) Delete the DTCs .
(b) Recheck for DTCs .
Result:






B -- USE SIMULATION METHOD TO CHECK
A -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - POWER 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.
3. CHECK HARNESS AND CONNECTOR (POWER 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 -- REPLACE CERTIFICATION ECU
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (POWER SWITCH BODY GROUND)





(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE CERTIFICATION ECU
OK -- REPLACE POWER SWITCH