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  #1  
Old 12-13-2005, 08:38 PM
96OhioSVX
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Trouble code P0748 HELP PLEASE

Code says I have a bad ground, a short to battery, or an open circuit condition in the electrical circuit for pressure control solenoid A. Ive had this car for about 9 months now and just had the original tranny, and both front and rear diffs rebuilt 7 weeks ago. Was something not done correctly or is this tranny going bad on me? Is there any quick fix or websites I can check out to fix the problem? The tranny and both front and read diff are under warranty for 1 year but Id hate to do away with my SVX for another 2 weeks it took them 3weeks to redo tranny because it had to be shipped to Washington state for the rubuild. PLEASE HELP!! tyvm
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  #2  
Old 12-14-2005, 07:15 AM
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Chiketkd Chiketkd is offline
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The code P0748 comes back as: "Pressure Control Solenoid Electrical"

My '96 would throw that code when I disconnected the dropping resistor that's mounted on the fender beside the battery:



You can also throw the code if solenoid A fails (which is inside of the trans and more expensive to replace).

Have you noticed any change in the way your car shifts? Does it feel 'firmer' in any way? Also, as your car is an OBDII, do you you get a flashing red light on start-up (it'll appear in the upper left hand corner of your gauge cluster)?

First check to make sure that the dropping resisitor (behind the battery) is plugged into the connector. If it is, then my advice would be to purchase a working used one from someone off of the network (brand new they cost $50-$60) and replace it.

If that doesn't work, then it's your solenoid A and you'll need to take it into your dealership or independent transmission shop and have them replace Solenoid A in your trans.

-Chike
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  #3  
Old 12-14-2005, 06:25 PM
96OhioSVX
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I have noticed a change as it shifts into 2nd it seems to be much sharper but doesnt happen often. The resinator that sits beside the battery looks brand new but was wondering if there is a way to test it. And I checked for the warning lights and on my way to work my AT oil light blinked 16 times but on my way home from work it didnt blink at all. tyvm for the info you provided, if you have any other words of wisdom to help me out its much appreciated. If the solenoid would happen to be bad is my car still driveable? Im suppoused to be driving out of town 600 mile round trip in a few days just wonderin if i should use a differnt vehicle.
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  #4  
Old 12-14-2005, 06:30 PM
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It's not a resonator, it's a resistor

You can test it by unplugging it and using an ohm-meter.
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  #5  
Old 12-14-2005, 07:23 PM
oab_au oab_au is offline
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Is it OK to drive?

If it is the A solenoid that is bringing on the light, it won't hurt to drive it, The changes will be a bit rough, and it will act strange on overun, but it won't hurt anything, or stop the car.

Harvey.
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  #6  
Old 12-14-2005, 10:59 PM
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Quote:
Originally Posted by 96OhioSVX
And I checked for the warning lights and on my way to work my AT oil light blinked 16 times but on my way home from work it didnt blink at all.
Correct - that's the blinking light I was referring to. In the '92-'95 models it's a 'power light' but in the '96-'97 models it's the red AT OIL light.

Like Harvey mentioned, the car's okay to drive. If the light only comes on ocassionally, whatever is causing the TCU to throw the code (solenoid A or the resistor) may be on the way out but not totally malfunctioning yet.

-Chike
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  #7  
Old 12-15-2005, 04:44 AM
96OhioSVX
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Lol sorry I didnt see the resinator typo I was home from lunch and rushed my post. So what should the ohms be for a good resistor? Gonna test that and change if its bad. If its good im going to send it back to Aamco and wait weeks again. tyvm for all your help its good to see a site like this youll be seein this name here alot
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  #8  
Old 12-17-2005, 05:17 PM
Sixpack Subaru
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Quote:
Originally Posted by 96OhioSVX
Code says I have a bad ground, a short to battery, or an open circuit condition in the electrical circuit for pressure control solenoid A. Ive had this car for about 9 months now and just had the original tranny, and both front and rear diffs rebuilt 7 weeks ago. Was something not done correctly or is this tranny going bad on me? Is there any quick fix or websites I can check out to fix the problem? The tranny and both front and read diff are under warranty for 1 year but Id hate to do away with my SVX for another 2 weeks it took them 3weeks to redo tranny because it had to be shipped to Washington state for the rubuild. PLEASE HELP!! tyvm
Inside the valve body, under the pan, you will see all your solenoids etc, (except duty/line pressure solenoid etc in rear housing), you will also see there is a small (yellow?), wire that earths all these solenoids, generally if you have an earth issue, it will affect ALL the solenoids so you can rule that one out!. The resistor you guys are talking about as I understand it, drops the voltage to the solenoids/auto to 10v for better solenoid longevity. But I don't think it will affect solenoid operation, unless it fails completely.
We had ALOT of issues with the duty solenoid(in rear of trans), remove ext housing and viscous coupling/transfer gear and you will see a small solenoid in the ext housing, make sure you order two gaskets first, you will see there is a steel plunger in an alloy housing with oil galleries in it. This is the valve that controls front to rear drive. Remove the steel plate that holds the sring in, (careful not to lose the spring!!), remove the spring and the plunger should "fall out under it's own weight", I can promise you that it won't, it will need to be removed gently without damage, then run it down with some 1200 of finer sand paper, wrap some paper around a screwdriver or simillar, and do the same to the sleeve/bore that the plunger fits into,(taking care not to damage the bore!). Make sure the valve will 'slide up and down' without the spring in it by shaking the housing, you should be able to hear it click when it moves. Then clean it all down with white spirit or simillar. Slap it back together and fill er up!!
Don't forget to mark your tailshaft for re-assembly to avoid vibrations. Make sure to order a new Ext housing gasket-if fitted. Make sure ALL clutch plates are aligned correctly with 'drive-drum' prior to re-torquing ext housing bolts.
Loctite t/shaft bolts. PHEW!!!
I thunk I straiyned miy fungers!!!

Cheers

Sixpack
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  #9  
Old 12-18-2005, 06:00 PM
oab_au oab_au is offline
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To clean or replace.

Well its a matter of if it is worth pulling the back end off, to clean the valve, instead of just replacing the whole C Solenoid assemble. Its not expensive, a lot cheaper than pulling the whole thing down, to clean the valve, assembling it back, only to find that you have cleaned the wrong valve, and do it again.

The valve you have discribed, is the Pilot Pressure Regulator valve, it has the strong spring to handle the line pressure. The Transfer valve is the smaller one with a lighter spring, to handle the lighter Pilot pressure. Thats why they stick.




Harvey.
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  #10  
Old 12-18-2005, 11:24 PM
Sixpack Subaru
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Talking

I have never replace the solenoid-No crap!! On ANY Subaru auto that runs it!!
No kidding!! We were always taught, (from when I was a second year in 1990!), to remove and clean the plunger as I described, I have tested dozens of solenoids and never had a problem!!LOL!
Do you suppose they sourced different parts for the US auto's??
They 'look' the same.....LOL!
Cheers
Sixpack
Edit; oh yeah, over here it is probably not 'inexpensive'LOL!

Last edited by Sixpack Subaru; 12-18-2005 at 11:26 PM.
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  #11  
Old 12-19-2005, 03:29 PM
oab_au oab_au is offline
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Quote:
Originally Posted by Sixpack Subaru
I have never replace the solenoid-No crap!! On ANY Subaru auto that runs it!!
No kidding!! We were always taught, (from when I was a second year in 1990!), to remove and clean the plunger as I described, I have tested dozens of solenoids and never had a problem!!LOL!
Do you suppose they sourced different parts for the US auto's??
They 'look' the same.....LOL!
Cheers
Sixpack
Edit; oh yeah, over here it is probably not 'inexpensive'LOL!
That assemble is out of a Aust. VTD box. The US Transfer one looks the same, but is a different part No. This one had the Transfer valve stuck in the on position causing binding, of the Limited Slip clutch.

The low pressure and the light spring, on the spool, seem to be too light. If the spool does not get a full travel, every now and again, it will stick, in the off, or when it does get to move, it sticks in the on position. The VTD one can be moved to full travel by fitting the "Diff lock" fuse, but that can't be done with the US one. So you need to exercise it with a bit of wheel spin every month or so.

Harvey.
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97 Liberty GX Auto sedan. 320,000Kls.
04 Liberty 30R Auto Premium. 92.000kls.
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  #12  
Old 12-20-2005, 04:44 AM
Sixpack Subaru
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OKAY DOKAY......
So maybe I wasn't TOO FAR wrong then aye>?
I'm not sure...but I may/should have mentioned that 'over here'...or something!!LOL!
Cheers Harvey
Sixpack
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