New SVX, new problems.

[TurboIQ]

Just got back from a trip to New Jersey. I steped up from a 95 L to a 96 LSi. Overall the car is in very decent shape, although the paint job on certain panels (especially the roof and the sunroof) could not possibly be ****tier.

Something fishy happened when I meet the owner. I went for a test drive, paying specific attention to the transmission's shifts, and noticed that the 3rd was starting to slip. Since I had to drive it for more than 500 miles on the way home, I decided to disconnect the resistor behind the battery to help shifts. The owner then replugged a vaccum line that was loose (purposely?). On the way back, 2 things: the check engine light went on, and the hot tranny fluid blinked 8 seconds whenever I restarted the car. Turns out that the OBDII code is "P0748: Pressure solenoid circuit malfunction". I wanted to know if unplugging the resistor might have causes either or both of the lights to go on, or if that unplugged vacuum hose might be responsible for the light coming back on.



My other concern is the power steering. I noticed that it harder to turn than my 95L, and assistance is virtually cancelled at about 30mph. Is that normal?

[TomsSVX]

Ok, the unplugged resistor will cause the atf fluid light to flash.

The solenoid sounds like it is for the engine codes??? I would imaging one of the emmision solenoids under the intake is creating a problem. he hooked up the cruise vacuum line (one on the firewall) that will not effect the engine's performance nor throw a code.

Am I missing anything??

Edit: powersteering is speed sensitive, check to be sure the plug on the steering rack is plugged in and check the fluid levels

Tom

[Hocrest]

The hose in that picture is for the cruise control.

[TomsSVX]

the pressure solenoid valve is also known as the pressure regulator. It is a black solenoid under the intake manifold on the passenger side

Tom

[TurboIQ]

Originally Posted by TomsSVX

the pressure solenoid valve is also known as the pressure regulator. It is a black solenoid under the intake manifold on the passenger side

Tom

That was fast! Thanks a lot for your aswers and your help. What does that solenoid do exactly?

[TomsSVX]

it regulates pressure to and from the charcoal canister. It is all part of the emissions system with collaboration with the EGR valve and such. Simple fix but its a PITA to get to

Tom

[TurboIQ]

Ok thank. On a different note, I was wondering if any of you had experimented with products limitting slippage in transmissions. I've heard of the "Dr Detroit" (local) additive and someone else told me to try a GM additive that they put in differentials when they start slipping. I know this exists, but since unplugging the resistor didn't seem to have made a difference, I doubt it's help.

[TomsSVX]

if your transmission is slipping there is no additive to save it sorry

Tom

[TurboIQ]

Originally Posted by TomsSVX

if your transmission is slipping there is no additive to save it sorry

Tom

I was afraid you were gonna say that.

Thanks.

[Trevor]

Do not jump to high cost conclusions. Get the line pressure tested. Low pressure can result from a worn solenoid "A", which can be replaced without removing the transmission. What is more there could be some other detectable cause not horribly expensive.

[TurboIQ]

I brought the car to the same mechanic who diagnosed the code (Subaru specialist), and he has acces to specific troubleshooting procedures (which I don't have with me at this moment) but it does refer to a transmission malfunction. If you look here down to P0748, the whole P07XX section seems to apply to transmission issues. Could unplugging the resistor throw that code?

[Manarius]

Originally Posted by TomsSVX

Edit: powersteering is speed sensitive, check to be sure the plug on the steering rack is plugged in and check the fluid levels

Tom

Tom, if the rack was unplugged, would that cause the steering light to be on? Mine isn't on at the moment, but I've driven other cars that are noticeably easier to steer than my SVX. The fluid level is full. Maybe it's just that the SVX has stiff steering?

[TomsSVX]

not sure about that. I do know some people have done that before

Tom

[Trevor]

Originally Posted by TurboIQ

I brought the car to the same mechanic who diagnosed the code (Subaru specialist), and he has acces to specific troubleshooting procedures (which I don't have with me at this moment) but it does refer to a transmission malfunction. If you look here down to P0748, the whole P07XX section seems to apply to transmission issues. Could unplugging the resistor throw that code?

Yes, quite likely disconnecting the resistor circuit could throw this code. The resistor circuit is in parallel with the related solenoid control circuit.

Code PO748 is shown as covering the transmission solenoid which regulates line pressure. This solenoid valve is pulse width modulated and has the most arduous duty of all as it is cycled continuously.

The code indicates an electrical problem rather than a mechanical fault in respect of the valve, and so ties in with the resistor. The valve is accessible by dropping the pan and without removing the transmission.


P.S. Plug the resistor back in if it is still disconnected and clear the codes. Fault codes are held in memory until cleared. If the code returns this will indicate an electrical problem with the solenoid which could very well be the reason for a low line pressure. If so, not too expensive to replace the solenoid.

[TurboIQ]

Excellent! Very helpfull info from all of you guys. Glad to be back in the SVX community!