DTC B2605: Battery Control Low

DTC detecting condition: 

When low voltage (9 V or less) or high voltage (16 V or more) continues for 10 seconds.

Trouble symptom: 

• Seat positions cannot be memorized.
• Seat operation is possible with manual operation, but not with memory function.

Wiring diagram: 

Power seat system Ref. to WIRING SYSTEM>POWER SEAT SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the DTC of [Power Seat Memory] using the Subaru Select Monitor. Ref. to Power Seat Memory System (Diagnostics)>Diagnostic Trouble Code (DTC) .

      Is a DTC other than DTC B2605 displayed? (Current malfunction)

      Yes  : Perform the diagnosis for the displayed DTCs.

      No  : Go to  2 .

2. CHECK DTC  .

   Make sure that DTC B2605 is not displayed as past malfunction.

   Is DTC B2605 displayed? (Past malfunction)

   Yes  : Perform the memory recall after re-registering the memory.

   No  : Go to  3 .

3. CHECK POWER SEAT CONTROL MODULE  .

   Using the Subaru Select Monitor, check the following items in the [Data monitor] of [Power Seat Memory]. Ref. to Power Seat Memory System (Diagnostics)>Data Monitor .

   • Battery Voltage

   Is the voltage 8 - 16 [V]?

   Yes  : Go to  5 .

   No  : Go to  4 .

4. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the power seat control module connector.
   3. Turn the ignition switch to ON.
   4. Using a tester, measure the voltage between the power seat control module connector and chassis ground.

      Connector and terminal 

      (St42) No. 18 (+) - Chassis ground (-):

      (St42) No. 24 (+) - Chassis ground (-):

      (St43) No. 1 (+) - Chassis ground (-):

      Is the voltage 8 - 16 V?

      Yes  : Replace the power seat control module. Ref. to SEATS>POWER SEAT SYSTEM .

      No  : Repair the open circuit of harness between the power seat control module connector and fuse.

5. CHECK BATTERY VOLTAGE  .

   Measure the battery voltage while the power seat is in operation.

   Is the voltage 8 - 16 V?

   Yes  : Ask the user if the power window or passenger's power seat was operated or cranking was performed while the driver's power seat was in operation.

   NOTE: Even when the battery voltage is normal under ordinary circumstance, the voltage may drop to 7.5 V or less in some cases, for example at cranking.

   No  : Check the battery. Ref. to STARTING/CHARGING SYSTEMS (H4DO)>BATTERY . Ref. to STARTING/CHARGING SYSTEMS (H4DOTC)>BATTERY .