DTC B2621: Mirror SW Anomalous State

DTC detecting condition: 

When any of operation statuses (up, down, left or right) of R side mirror surface switch continues for 12 seconds.

Or,

When any of operation statuses (up, down, left or right) of L side mirror surface switch continues for 12 seconds.

Trouble symptom: 

Mirror surfaces do not move even when the mirror surface switch is operated.

Wiring diagram: 

Remote control mirror system Ref. to WIRING SYSTEM>REMOTE CONTROL MIRROR 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 (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2621 displayed? (Current malfunction)

   Yes:  Go to  2 .

   No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time.

   Reproduce the failure, and 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 REMOTE CONTROL MIRROR SWITCH  .

   Check remote control mirror switch unit. Ref. to GLASS/WINDOWS/MIRRORS>REMOTE CONTROL MIRROR SWITCH .

   Is the remote control mirror switch OK?

   Yes:  Go to  3 .

   No:  Replace the remote control mirror switch. Ref. to GLASS/WINDOWS/MIRRORS>REMOTE CONTROL MIRROR SWITCH .

3. CHECK HARNESS (SHORT CIRCUIT TO POWER SUPPLY)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the Power Seat and Remote Control Mirror control module connector.
   3. Disconnect the remote control mirror switch connector.
   4. Turn the ignition switch to ON.
   5. Using a tester, measure the voltage between Power Seat and Remote Control Mirror control module connector and chassis ground.

      Connector and terminal 

      (R502) No. 5 (+) - Chassis ground (-):

      (R502) No. 6 (+) - Chassis ground (-):

      (R502) No. 14 (+) - Chassis ground (-):

      (R502) No. 15 (+) - Chassis ground (-):

      (R502) No. 16 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes:  Go to  4 .

   No:  Repair the short circuit to power supply in harness between Power Seat and Remote Control Mirror control module connector and remote control mirror switch connector.

4. CHECK HARNESS (GROUND SHORT CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Using a tester, measure the resistance between Power Seat and Remote Control Mirror control module connector and chassis ground.

      Connector and terminal 

      (R502) No. 5 - Chassis ground:

      (R502) No. 6 - Chassis ground:

      (R502) No. 14 - Chassis ground:

      (R502) No. 15 - Chassis ground:

      (R502) No. 16 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes:  Replace Power Seat and Remote Control Mirror control module. Ref. to SEATS>POWER SEAT SYSTEM .

   No:  Repair the short circuit to ground in harness between Power Seat and Remote Control Mirror control module connector and remote control mirror switch connector.