B278A

THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILIZER SYSTEM: B278A: Short to GND in Immobilizer System Power Source Circuit
B278A - Short to GND in Immobilizer 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:
If the certification ECU (smart key ECU assembly) is replaced, register all the keys Engine Immobilizer System.

PROCEDURE

1. CHECK DTC OUTPUT

(a) Clear the DTCs Engine Immobilizer System.

(b) Recheck for DTCs Engine Immobilizer System.

OK:

DTC B278A is not output.

NG -- CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ENGINE SWITCH)

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

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

(a) Disconnect the certification ECU (smart key ECU assembly) connector.

(b) Disconnect the engine switch connector.

Text in Illustration

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

3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (ENGINE SWITCH - POWER SOURCE AND BODY GROUND)

(a) Reconnect the certification ECU (smart key ECU assembly) connector.

(b) Reconnect the engine switch connector.

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

Standard Resistance:

Result:

Text in Illustration

C -- REPLACE ENGINE SWITCH Removal

B -- REPLACE ENGINE SWITCH Removal

A -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal