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View Full Version : Trying to match TCU with ECM :-?



eseiler
10-11-2006, 09:05 AM
Hello all,
I have a 96 Legacy outback with an auto tranny retrofitted with a EJ22 engine from a 95 legacy. I recently acquired a whole bunch of TCUs and ECMs from varios models and years of Legacies and Legacy Outbacks.

After the engine swap, the ECM came on (throws a code of something to do with the EVAP canister). I figured no biggie...kept on driving.
Recently, however, I began to have tranny problems (flashing AT Oil light on startup) and I swapped in a TCU from a 96 OB and problem solved...for a while. One day I put the engine in reverse and backed up hard...TCU light flashing again.

I'm guessing that a permanent solution to these electronic problems is properly matching an ECM and TCU to the engine and transmission.

The code on the original TCU was 'PH' the one in there now is 'PB'. I have a whole bunch of TCUs and ECMs with various two-letter codes.

What I am trying to do is find compatible ECM and TCU combinations which hopefully will permanently solve the problem.

Thanks for your input.

Regards,
Damien

Huffer
10-11-2006, 10:07 AM
I get the AT Oil Light flashing at me every so often. Original computer & original ECM/ECU.

It's not a problem as long as the light doesn't stay solid.

eseiler
10-11-2006, 12:10 PM
I get the AT Oil Light flashing at me every so often. Original computer & original ECM/ECU.

It's not a problem as long as the light doesn't stay solid.

OK but there are actual problems with the transmission. Namely, the rear transfer clutch has a tendency to stay engaged. This causes a loud 'clunking' noise sometimes when shifting from D to R or P (particularly after having driven the vehicle for a few miles).


--Damien

Huffer
10-11-2006, 01:36 PM
Sounds to me like it's a mechanical issue with the AT then, not an electronic issue.

Have you drained the AT and inspected for metal shavings at all?

The ATs from those years are pretty much the same.

eseiler
10-11-2006, 02:37 PM
Sounds to me like it's a mechanical issue with the AT then, not an electronic issue.

Have you drained the AT and inspected for metal shavings at all?

The ATs from those years are pretty much the same.

Yeah already did a full flush...a new TCU solved the problem last time. It seems those electronic components are awfully sensitive...four different ECMs designed for an EJ22 of the same model year would not turn my engine over.

Is there some way they have to be energized before they will function properly?

--Damien

Huffer
10-11-2006, 03:01 PM
Sorry, I have nothing on this.

Maybe you could contact Subaru to get them to match a TCU & ECU with the AT serial#?

Reason
10-11-2006, 10:20 PM
If you need an ECU from a 96 GT I have one I don't need!