I had this go on when I was working on the mass air pressure sensor, after disconnecting the plug.   After reconnecting it it went away but is now on constantly.   I've gone over possible loose wires or hoses on top of the engine for my 2002 Forester and don't see anything loose.   I replaced the mass air pressure sensor.   

I'm thinking I may have triggered a short in the system.   The Forester is now almost undriveable.  Lots of jerks, losses of power when going down the street.  Prior to this it was just running with lack of power at higher speeds.  Thanks in advance for any trouble shooting help.   I'm getting the p122 and 731 codes.   

Edited February 20, 20242 yr by ThosL

Check the ATF fluid level. 

Are there any engine codes?

1 hour ago, idosubaru said:

Check the ATF fluid level. 

Are there any engine codes?

The engine is running fine.   260k or so miles.  Shifting very rough; tranny fluids are fine.  Must be solenoids from all I see online.  

10 hours ago, ThosL said:

The engine is running fine.   260k or so miles.  Shifting very rough; tranny fluids are fine.  Must be solenoids from all I see online.  

Are there any engine codes (check engine light)? Not saying this to be mean but for clarity: running well isn’t important - are there any check engine engine lights or codes?

Check if the ATF pan is dented. It can cause problems much easier than a dented engine oil pan. 

You can attempt to extract the AT codes:

some newer Subarus like 2005 ish I think but I forget the years, I have a very easy way to read the codes without any scanner. Not sure it applies to 2002  

or the classic schizophrenic multiple personality disorder meth smoking strategy Subaru employed here which you can do yourself with no scanner:

 

 

7 hours ago, idosubaru said:

Are there any engine codes (check engine light)? Not saying this to be mean but for clarity: running well isn’t important - are there any check engine engine lights or codes?

Check if the ATF pan is dented. It can cause problems much easier than a dented engine oil pan. 

You can attempt to extract the AT codes:

some newer Subarus like 2005 ish I think but I forget the years, I have a very easy way to read the codes without any scanner. Not sure it applies to 2002  

or the classic schizophrenic multiple personality disorder meth smoking strategy Subaru employed here which you can do yourself with no scanner:

 

 

I saw that series of shift tests elsewhere, will try it tomorrow.

I spoke to several different transmission shops and garages yesterday; unfortunately once you commit to having a transmission shop checking out or working on your car it gets quite expensive quickly.   From what I've seen they often will not do limited work, ie one transmission solenoid, but want to do the whole valve body.  No there is no damage to the transmission, dents, burned fluid etc..  

A good Trans Shop will be able to scan the trans a bit deeper than the flashing light.  They should be able to identify the fault/s.

Once they do that, you can always take that information and do the repair yourself.

An emissions shop sent me to the "National Transmissions" shop; said they'd diagnose it for fifty bucks, leave it for the day until they get to it.  I spoke to a couple Hispanic shops, they don't have a lot of experience with transmissions and don't like to get into that type of work.  Croce Transmissions charges $180 for a thorough diagnosis, I avoided stopping at Aamco, has some problem reviews, "free" diagnosis.  The car is driveable but should it be driven in rough shape? I did the trip on bicycle yesterday.

This is a good video on replacing solenoids:

I'm went through the trouble shooting procedure, just two flashes a second so no special codes, just 731 and 122.

Edited February 22, 20242 yr by ThosL

When I finally got a mechanic to check out the Forester today, the P122 stood out, and he said that until that was addressed, transmission diagnosis and work would be ineffective.   I remember that I had pulled the sensor off the throttle body and put it  back without examining alignment thinking that that was automatic.  The mechanic saw the mark on the throttle body and mentioned that.  After readjusting the sensor and aligning it properly, the Forester ran like a top.