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90 Legacy Atmospheric Sensor


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37 replies to this topic

#1 Richard1296

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Posted 09 July 2006 - 01:33 PM

I have a transmission code I read off of the power light.
Code is 22...Atmospheric Sensor. Where is it on a 90 Legacy.
And the transmission has a Atmospheric Sensor ????
I assume this is why it won't go into AWD, don't seem
to have any kind of bind, and the transmission works fine.

Richard1296

#2 NorthWet

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Posted 09 July 2006 - 02:48 PM

According to my *92* FSM, it is a signal from the ECU, and the error indicates an open- or short-circuit on this wire. Manual says to replace ECU...

I would check the physical wiring first, maybe reseat connectors to the ECU and TCU.

#3 Richard1296

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Posted 09 July 2006 - 03:03 PM

According to my *92* FSM, it is a signal from the ECU, and the error indicates an open- or short-circuit on this wire. Manual says to replace ECU...

I would check the physical wiring first, maybe reseat connectors to the ECU and TCU.



And where are these control modules. After doing a diagnostic to find these
codes they go away until the car is driven.
Where is the wire and its color if you can tell.
Strange I can "clear" them and they return.
This is my first Subaru....bought it as a daily driver and its a great car
excepppt the AWD doesn't work....I assume because of the 22 code.

Thanks
Richard1296

#4 NorthWet

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Posted 09 July 2006 - 04:45 PM

According to the FSM, the APS is used to control how firm the transmission shifts relative to altitude. Does not say anything regarding effecting AWD functioning.

FSM says that it is on the B44 connector, pin9. Helps alot, right? Looks like the TCU has 3 connectors in a row on it, with one connector (B33) slightly wider (across its minor dimension). Next to it is B44, and there is a "step" where the wider B33 "steps upwards" towards the narrower B44. B44 pin 9 is on the edge with this "step", 4th pin in from the step.

The FSM implies that the TCU is near the steering column, and warns that it is also near the airbag control module (92 FSM).

#5 Richard1296

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Posted 09 July 2006 - 05:10 PM

Does the manual give an indication of how much trouble
to change the module. I think a local "salvage yard" has
several Legacy's for me to get parts off of.
I guess all modules are the same

Thanks Again
Richard1296

#6 Legacy777

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Posted 09 July 2006 - 05:48 PM

Was the power light blinking at start up, or do you have a constantly lit power light?

Can you please elaborate what you mean by the transmission not going into AWD.

The atmospheric pressure sensor is located inside the ECU. There is a wire that allows the TCU to read the atmospheric pressure sensor from the ECU.

Here is a pic of the ECU & TCU location.
http://www.main.expe...ges/ecuhide.jpg

#7 nipper

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Posted 09 July 2006 - 05:50 PM

Was the power light blinking at start up, or do you have a constantly lit power light?

Can you please elaborate what you mean by the transmission not going into AWD.

The atmospheric pressure sensor is located inside the ECU. There is a wire that allows the TCU to read the atmospheric pressure sensor from the ECU.

Here is a pic of the ECU & TCU location.
http://www.main.expe...ges/ecuhide.jpg


yes explain further

nipper

#8 Richard1296

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Posted 09 July 2006 - 06:45 PM

OK I shall elaborate.
When I start the car the power light flashes 16 times. The 16 flashes
is just to get attention and is not a code. By going through the semi-
elaborate procedure of shifting through the gears, pushing the power
button on/off, and turning the ignition on/off , the light can be made
to flash the code 22 (two long two short flashes) . Since this is a
transmission code I was hoping it is why there is no AWD.
The AWD works fine with all 4 wheels off the ground. When in loose
gravel (and snow last winter) the AWD only works for a second then
kicks out, even when the front wheels are still spinning, the rear
is just along for the ride.
The car runs great, uses no oil (180,000 miles), does not leak (unusual)
and the transmission shifts perfectly, maybe a bit crisp in the 1-2 shift
if on the gas just a little, but not harsh by any means. I can go through
the diagnostic procedure that is similar to the code retrieval process
and the code 22 will go away ....until the car is driven some. I can
move the car foreward and reverse in the driveway and the code remains
gone. A drive arounnd the block and it comes back.
One Subaru dealer said it was an electrical problem , a second Subaru
dealer said it was the clutch pack in the AWD.
I don't mind paying to get it repaired.....I just don't want someone to continually
swap out parts at my expense till he stumbles on the problem.
I got the car at a very good price since the owner told me the AWD
didn't work, I just hope I can get it working without rebuilding the whole car.
And thanks all for the help, I'm new to Subaru's. Though if the 0%
financing returns I may get a new Impreza ...and keep the 90 too.
That'll be 2 Mustangs, a F-150, a Hyundai, and 2 Subaru's.
And its just me and the wife.
Did I elaborate enough

Thanks All
Richard1296

#9 nipper

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Posted 09 July 2006 - 06:49 PM

Damn its raining torque bind and tranny problems...

NO ONE PARK NEAR MY CAR! i dont want it catching whats going around

Richard whats your email, i have some info for you

nipper

#10 Richard1296

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Posted 09 July 2006 - 07:08 PM

Damn its raining torque bind and tranny problems...

NO ONE PARK NEAR MY CAR! i dont want it catching whats going around

Richard whats your email, i have some info for you

nipper


Sent you a PM with my email
Sent you 2 PM's...one with my email

Thanks
Richard1296

#11 Legacy777

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Posted 10 July 2006 - 11:34 AM

As I mentioned, the atmospheric pressure sensor is located in the ECU, and the TCU reads it from there.

Check out these scans of the TCU i/o
http://www.main.expe...U_I-O_page1.jpg
http://www.main.expe...U_I-O_page2.jpg

This manual has a wiring diagram that shows what I'm talking about on page 322
http://www.main.experiencetherave.com:8080/subaru_manual_scans/1992_FSM_(Engine_%26_Electrical)/

Check the wiring between the ECU & TCU. If it's fine, then that could indicate the atmospheric pressure sensor in the ECU is bad. Or the TCU is acting up.

You should be able to find used ECU's or TCU's for a reasonable price in the marketplace.

#12 Richard1296

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Posted 10 July 2006 - 03:57 PM

As I mentioned, the atmospheric pressure sensor is located in the ECU, and the TCU reads it from there.

Check out these scans of the TCU i/o
http://www.main.expe...U_I-O_page1.jpg
http://www.main.expe...U_I-O_page2.jpg

This manual has a wiring diagram that shows what I'm talking about on page 322
http://www.main.experiencetherave.com:8080/subaru_manual_scans/1992_FSM_(Engine_%26_Electrical)/

Check the wiring between the ECU & TCU. If it's fine, then that could indicate the atmospheric pressure sensor in the ECU is bad. Or the TCU is acting up.

[/I]
You should be able to find used ECU's or TCU's for a reasonable price in the marketplace.



I don't suppose you have a manual for the transmission .

Thanks
Richard

#13 NorthWet

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Posted 10 July 2006 - 04:03 PM

Legacy777 should (that is where he got the scans) and so do I. What do you need?

#14 Richard1296

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Posted 10 July 2006 - 04:40 PM

Legacy777 should (that is where he got the scans) and so do I. What do you need?



The transmission service manual...or as much info as I can get

Thanks
Richard

#15 NorthWet

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Posted 10 July 2006 - 05:06 PM

The auto tranny section of my 92 FSM is 219 pages. Narrowing things down would help, as it would be difficult/impractical (at the moment) to scan the whole thing.

#16 nipper

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Posted 10 July 2006 - 05:20 PM

The auto tranny section of my 92 FSM is 219 pages. Narrowing things down would help, as it would be difficult/impractical (at the moment) to scan the whole thing.


some people just arent helpful :banana: :D

nipper

#17 Richard1296

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Posted 10 July 2006 - 06:40 PM

The more I mess with the car the less I know.
I fixed the CEL... It didn't work at all, Now I
got lotsa trouble codes (45,35,32,22)
from the ECU and also a 22 from the TCU.
Again the car runs fine, starts fine, and gives
good fuel mileage.
I think I may have to resort to a Subaru dealer.

Richard1296

#18 NorthWet

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Posted 10 July 2006 - 06:53 PM

Are these old (stored) codes or new? To avoid confusion, I would clear codes and start fresh to see what is current. If these are all new, I would look to some systemic problem, like a bad connection to the ECU. Check grounding of the ECU, and reseat all of the connectors to it, and maybe some of the connectors in the engine compartment.

#19 nipper

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Posted 10 July 2006 - 07:03 PM

The more I mess with the car the less I know.
I fixed the CEL... It didn't work at all, Now I
got lotsa trouble codes (45,35,32,22)
from the ECU and also a 22 from the TCU.
Again the car runs fine, starts fine, and gives
good fuel mileage.
I think I may have to resort to a Subaru dealer.

Richard1296


reset the puter. Check the codes if they come up again and list them all here. We can maybe trace them out. See what the common denomination is, maybe they are all on the same wire loom.

nipper

#20 Richard1296

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Posted 10 July 2006 - 07:49 PM

It will be tomorrow evening till I can reset the computer.
I assume removing the ECU fuse and restarting the car
and letting it idle till warmed up. The wife will probably
drive it in the morning to work and back (1 mile)
I can remove the fuse and let it sit for about 30 minutes
and then replace the fuse and let it idle till warm.
Then rejoin the black connectors and read the codes on the
CEL.
the code 45 is usually terminal (bad ECU) if I read the
manual provided by 777 Legacy correctly. Wish you had a
transmission manual in.zip like the engine/electrical you
provided.

I thank you all for your helping me this far.
I will trouble you some more tomorrow.

Thank You
Richard1296

#21 Legacy777

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Posted 10 July 2006 - 08:48 PM

My recommendation would be to keep your eye out on ebay for factory manuals. As NorthWet mentioned, the trans manual is rather large, and scanning the whole thing is a chore.

I have some additional random scans here
http://www.main.expe...cans/FSM_Scans/

Code 45 is the atmospheric pressure sensor code. It doesn't mean the ECU is bad, but if the atmospheric pressure sensor is bad, then you'll have to replace the ECU.

Definitely replace the ECU and check the wiring.

#22 Richard1296

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Posted 11 July 2006 - 08:07 PM

A complete reset of the computer has cleared the 22, 32, and 35
error codes. I figure a little driving tomorrow will find out if they
will return . Letting the car run for about 10-15 minutes in the driveway
and shutting it off and restarting and then reading for codes the only
code left was a 45....atmospheric sensor bad. I will reset it one more time
and if the 45 remains then I guess I need to find a ECU. It is Subaru
# 22611-AA382. Anyone know if other ECU's can be substituted or
not. I have no idea whats available locally, and internet pricing
ranges from $175 for a used one to $500 for a new one.
Thanks all for the help so far. More on this saga to come.

Thanks
Richard1296

#23 Cougar

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Posted 11 July 2006 - 10:28 PM

Before condeming the sensor I would check the connections to it and even inside the ECU to make sure that the wiring is good. If it is bad you may be able to just replace the sensor itself.

#24 Legacy777

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Posted 12 July 2006 - 01:25 PM

Blackbart should be able to get a hold of an ECU for you. Any Automatic based (JECS) ECU for the 90-91 legacies should be interchangable.

If you have one that you think may be in question, post the number and I can check it.

#25 Richard1296

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Posted 12 July 2006 - 03:46 PM

Blackbart should be able to get a hold of an ECU for you. Any Automatic based (JECS) ECU for the 90-91 legacies should be interchangable.

If you have one that you think may be in question, post the number and I can check it.


According to my semi-local Subaru service department the following numbers
should all interchange and work.
22611-AA380
22611-AA381
22611-AA382
22611-AA383
I hope they know what they are talking about
1990 Legacy LS automatic build date 10/89
I don't have the numbers off of mine.
How hard is the computer to get to. I'm 6 foot and 210 pounds.
Getting under the dash ain't as easy as it once was.

Thanks
Richard




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