Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc b278d id code box judgment circuit

Subaru Legacy BN/BS (2015-2019) Service Manual / Keyless access with push button start system (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc b278d id code box judgment circuit

DTC DETECTING CONDITION:

When the evaluation of the ID code box setting circuit via the hard wire is judged as none, ID code box communication is received. (at new registration)

TROUBLE SYMPTOM:

Initial registration for the access key is not possible.

CAUTION:

For replacement procedure of keyless access CM, refer to the “REGISTRATION MANUAL FOR IMMOBILIZER” provided as a separate volume.

WIRING DIAGRAM:

NOTE:

For the coupling connector, refer to “WIRING SYSTEM”.

Keyless access with push button start system Keyless Access With Push Button Start System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK DTC. 1) Turn the ignition switch to OFF. 2) Using the Subaru Select Monitor, clear the memory of «keyless access with push button start». Clear Memory Mode 3) Turn the ignition switch to OFF > ON. 4) Read DTC using the Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is DTC B278D displayed-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B278D ID CODE BOX JUDGMENT CIRCUIT	Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2.CHECK HARNESS. 1) Disconnect the keyless access CM connector. 2) Measure the resistance between keyless access CM connector and chassis ground. Connector & terminal (i241) No. 23 — Chassis ground:	Is the resistance 10 k- or more-	Replace the keyless access CM. Keyless Access CM	Repair or replace the short circuit of the harness.

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