Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc b2793 back up power

Subaru Legacy BN/BS (2015-2019) Service Manual / Keyless access with push button start system (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc b2793 back up power

DTC DETECTING CONDITION:

When a fault occurs in +B2 power input for the keyless access CM.

TROUBLE SYMPTOM:

None

CAUTION:

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

WIRING DIAGRAM:

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

STEP	CHECK	YES	NO
1.CHECK CURRENT DATA. Check the current data display of «Keyless access with push button start» using Subaru Select Monitor. Read Current Data «ECM power supply voltage (back-up)»	Is «ON» displayed-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2793 BACK UP POWER	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2793 BACK UP POWER
2.CHECK DTC. 1) Using the Subaru Select Monitor, clear the memory. Clear Memory Mode 2) Start the engine, and let it idle for 40 seconds or more. 3) Read DTC using the Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is B2793 displayed-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2793 BACK UP POWER	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.
3.CHECK FUSE. Check the fuse. Relay and Fuse > INSPECTION	Is the fuse OK-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2793 BACK UP POWER	Replace the fuse. When the replaced fuse is blown immediately, check the power supply circuit for short-circuited.
4.CHECK HARNESS. 1) Disconnect the keyless access CM connector. 2) Using a tester, measure the voltage between the keyless access CM connector and chassis ground. Connector & terminal (i241) No. 40 (+) — Chassis ground (−):	Is the voltage 9.5 — 16 V-	Replace the keyless access CM. Keyless Access CM	Repair or replace the open circuit of harness.

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