Subaru Outback Forums banner

2011 Outback P0700, P0890, P2764: Location and Part Number of TCM Power Relay ("Self Shut Relay")

329 Views 8 Replies 2 Participants Last post by  Rymar
My son-in-law had their 2011 Outback show the following error codes.
P0700 - TCM says there is a problem
P2764 - Lock-up duty solenoid is faulty or output signal circuit is shorted
P0890 - Power supply circuit of TCM is open or shorted; Self shut relay malfunction

There were no noticeable drivability issues with the car, and it was not below freezing (so it seems like TSB 11-200-20R does not apply).

I did a bunch of searching, both on subaruoutback.org, and on the the web in general, and can't find many cases of a P0890 error. I'm focusing on this electrical problem, since this affects the main solenoid power supply to the TCM, and this could then cause the P2760 solenoid error. I think "self-shut" really means "self-shutoff", but I'm not sure. P0890 is also shown as "TCM Power Relay Error" for other cars/models.

From the FSM, here is the drawing for P0890:
Font Rectangle Parallel Slope Number


While I couldn't find any instances of a P0890 error actually requiring replacement of this relay, I would like to be able to identify where this relay is located in the car, and what the part number is. I've been unable to find any location info in the FSM, or any part number after searching multiple Subaru OEM parts sites, including parts.subaru.com.

One clue is that the relay plugs into connector B494. Looking in the Wiring section of the FSM shows this drawing. At the lower left, which I think is just next to the interior fusebox, is B494.
Vertebrate Organism Font Art Auto part


In the online parts guide, the closest info I could find was this (could they have made this more difficult to read?):
Rectangle Font Parallel Pattern Screenshot

Which, if you can read it, shows the "SELF SHUT RELAY" on "FIG.184". But there is no link, and no way to find where "FIG.184" is!

I found this drawing which shows a relay (circled in yellow) on the lower left of the interior fusebox, about where B494 probably is in the car. It also says FIG.184. But no part number is given.
Font Parallel Slope Rectangle Pattern



I don't have access to the car, so I can't check for a connector which looks like B494 at this location: it should have 4 contacts, and be "at the end" of a wiring harness, as shown above.

My son-in-law cleared the error codes using an OBD code reader, but they reappeared today. He is also trying disconnecting the battery for 10 minutes, as there were recently 2 different incidents where the battery was drained. Perhaps the TCM logged this error, and is now sending it repeatedly to the ECM?

Thanks for any info.
1 - 3 of 3 Posts

· Premium Member
01 VDC, 05 R Sedan, 06 BAJA EJ257
Joined
·
19,133 Posts
I would replace the battery, make sure the grounds are good and then check the valve body function. It may be a bad solenoid, but it could also be power supply in general.
 

· Premium Member
01 VDC, 05 R Sedan, 06 BAJA EJ257
Joined
·
19,133 Posts
All the ground connections in the engine bay are for electrical operation and computer feed. If there is one bad ground, the others are probably in the same condition.

A good scan tool that can see TCM data will allow you to see TCC lockup and Transfer Duty for the AWD. Some phone apps like Blue Driver will also let you see transmission data. TCC lockup condition can be verified by TCC Slip speed variations when the TCM commands a lockup.
 
1 - 3 of 3 Posts
Top