Check Engine light was on, Cruise light flashing, drove fine, checked codes, DTC P0700 (Transmission Control System [MIL Request]) was listed by a Snap-off scanner, and a palm pilot w/OBD II. Here is the fun part... the 05 model year book for Legacy AND Forester (dealer/factory service manual, section H4SO) say "refer to 4AT (D) diag" for diagnosis and repair, yet P0700 is not listed as a code in the Automatic Transmission book, it starts at P0705....

 

All I have found so-far on th' net is to R&R the TCU, but that leads me to ask "why?".

 

Does someone out there have the diagnostic trouble-tree for this code? I am not looking for "the fix" (if you have it, that would be helpfull) I just want to diagnose for myself and repair as necessary, but don't want to whittle away my time banging my head against a wall...

 

I may call in a favor to an old contact at a Suby dealer, but would probably have to drive there to have it hooked up to the "mother ship" but that just wouldn't be as fun as diving under their dash for ????????

 

Lewis

Check Engine light was on, Cruise light flashing, drove fine, checked codes, DTC P0700 (Transmission Control System [MIL Request]) was listed by a Snap-off scanner, and a palm pilot w/OBD II. Here is the fun part... the 05 model year book for Legacy AND Forester (dealer/factory service manual, section H4SO) say "refer to 4AT (D) diag" for diagnosis and repair, yet P0700 is not listed as a code in the Automatic Transmission book, it starts at P0705....

P0700 is the code that's set when the TCU detects a problem and "asks" the ECU to turn on the MIL ("MIL Request").

 

 

All I have found so-far on th' net is to R&R the TCU, but that leads me to ask "why?".

While you could have a defective TCU, P0700 is a very "generic" code, and further diagnosis needs to be done before condemning the TCU.

 

 

Does someone out there have the diagnostic trouble-tree for this code? I am not looking for "the fix" (if you have it, that would be helpfull) I just want to diagnose for myself and repair as necessary, but don't want to whittle away my time banging my head against a wall...

There's really not a "tree" for P0700; it's basically there to inform that further investigation is needed, which explains "refer to 4AT (D) diag". Was P0700 the only code? If so, then the TCU was unable to pass along more info to the ECU, and the TCU itself needs to be checked for further data.

 

 

I may call in a favor to an old contact at a Suby dealer,[...]

In this instance, that may be your best bet.

Here's the trick... how does one check trans codes w/o a Subaru Select Monitor? Best scenario I know of is to plug in the ground wire into the black 6-pin connector, place in "D" turn key off, on, shift down to "1" press accelerator to floor, release-holding half way, release completely, "AT TEMP" light flashes code... is this the prescribed method for an '05 Forester? I am doubting it at this point as Subaru is making it harder for those not in the dealer network.

 

 

I will attempt to check them at this time, and will get back later....

 

Lewis

This is out of the 05 Forester manual

7. Read Diagnostic Trouble

Code (DTC)

A: OPERATION

Refer to Subaru Select Monitor for information

about how to obtain and understand DTC. <Ref.

to 4AT(D)(diag)-15, OPERATION, Subaru Select

Monitor.>

NOTE:

DTC can not be read through AT OIL TEMP warning

light.

 

Looks like your taking a trip to your dealer friend , he can also reflash the TCM or ECM for some updates if they apply

 

SEA#3

Great! Just what I wanted to do. Drive an hour out of town to have him check it for me. The biggest question is... why hasn't the dealer fixed it yet? It has been in five times with no progress towards a solution, and where told to (Paraphrasing...) "pound sand, nothing can be done".

 

So I guess off to another dealer to continue the saga....

 

Thanks for the input, I'll update as info comes along.

 

Lewis