DTC B2793: Backup Power

DTC detecting condition:

When +B power supply (SUB) input is less than 9.5 V continuously for 10 seconds with ignition switch ON. (Voltage check is executed every one second)

Wiring diagram:

Keyless access with push button start system Ref. to WIRING SYSTEM>KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

For replacement procedure of keyless access control module, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.
Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>General Description>CAUTION .

CHECK DATA MONITOR .
1. Turn the ignition switch to ON.
2. Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Keyless Access with Push Button Start]. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DATA MONITOR .
  - Control Module Voltage(Backup)
Is [ON] displayed?

Yes : Go to 2 .

No : Go to 3 .
CHECK DTC .
1. Using the Subaru Select Monitor, perform the clear memory of [Keyless Access with Push Button Start]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
2. Start the engine, and let it idle for 40 seconds or more.
3. Read the DTC of [Keyless Access with Push Button Start] using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B2793 displayed? (Current malfunction)

Yes : Go to 3 .

No : 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.
CHECK FUSE .
Check the fuse. Ref. to SECURITY AND LOCKS>RELAY AND FUSE>INSPECTION .

Is the check result OK?

Yes : Go to 4 .

No : Replace the fuse. When the replaced fuse is blown immediately, check the power supply circuit for short-circuited.
CHECK HARNESS .
1. Turn the ignition switch to OFF.
2. Disconnect the keyless access control module connector.
3. Turn the ignition switch to ON.
4. Using a tester, measure the voltage between the keyless access control module connector and chassis ground.
  Connector and terminal
  
  (i75) No. 1 (+) - Chassis ground (-):
Is the voltage 9.5 - 16 V?

Yes : Replace the keyless access control module. Ref. to SECURITY AND LOCKS>KEYLESS ACCESS CONTROL MODULE .

No : Repair or replace the open circuit of harness.