[AeroForce]

2003 SAAB 9-3 Linear (5 speed)
CEL=P0033
Turbo Charger Bypass Valve Control Circuit

during acceleration, boost will increase normally, but stop at about half pressure on the mark. It is a precise point where the pressure stops building.

sometimes the car will start normally, but spontaneously begin getting half pressure after driving for a few minutes. other times it will just have the problem the whole drive. BUT sometimes if i restart the car while rolling, it will fix the problem. 5 days ago, the cel turned off and it worked again, but the problem came back 2 days later.

 

[Dfunk415]

There is a problem with your air bypass system. The reason it is doing this is to protect your throttle plate from a large amount of compressed air smashing into it. One of your control valves is probably clogged or broken. Mine was broken and it ran like this until it started shutting itself off completely. Since this is a recirculating system you have a vaccum line that runs from your throttle intake pipe to a control valve under your engine cover in between your throttle body and ecu. It has 3 vaccum lines in it. One in, one to the manifold, the other runs out and around the back of the engine to another control valve by the compressor. You need to check both of them and replace as needed. I got it directly from a saab dealership for like $35.

 

[AeroForce]

no obvious leaks or cracks.
i unplugged the cable that connects to the sensor on the tube that leads to the intake manifold (i think). its on the black tube that goes from the engine block to the bottom right corner of the hood, and the sensor thing is almost touching the battery. anyways, i disconnected it and it was basically the same story. I plugged it back in and it was working perfectly (for the time being). it will probably stop working on my way to school tomorow. im thinking its a bad connection or just a bad sensor.

 

[Dfunk415]

Check the one by the compressor just to be sure.

 

[Dfunk415]

You were checking one of the 2 sensors that reads the amount of boost running through the pipes. I meant the air bypass controll valves. If one of these are messed up there is no where for the spooled up air to go after the throttle plate closes. Your engine is preserving itself so to not become damaged. Just pop the engine cover off and have a look and check the one on top of the turbo compressor.

 

[AeroForce]

but theres no problem with the release of pressure, theres only a problem with building it. on another note, a few months ago my car would make a certain noise. whenever the rpms were at 2800 and i was COMPLETELY off the gas pedal, it would make a sort of rattling noise for half a second. but this noise seemed to go away when this boost problem started happening.

 

[ctrlz]

Bypass control valve is what I am touching in this photo:
http://www.saabcentral.com/forums/attachment.php?attachmentid=2206&d=1120305068

Boost control valve sits atop the wastegate actuator over by the compressor side of the turbo.

I would check the hoses for obvious cracks. If cracks not present, I would assume the solenoid (i.e "bypass control valve") is sticking and replace it. Very easy to access, and not expensive (relative to price of other parts), so worth a try just to swap a new one in. If that fails, then you are faced with more tedious troubleshooting like looking at electrical connections, etc.

 

[AeroForce]

yeah i saw that when i took off the engine cover
ill order a new one. thanks

 

[AeroForce]

wow. i cant find the part anywhere online.
do you have a link?

 

[Dfunk415]

Go to the dealership tomorrow. It only cost me like $38. Mine was broken after a dealership replaced my radiator. The bad part is, they tried to silicone it back together but the damage was done.

 

[AeroForce]

ok. thanks!

 

[AeroForce]

bought a new air bypass valve for $40.04 (the thing ctrlz is touchin in the pic)
took the old one out (PAIN IN THE ***)
put the new one (pretty easy)
doesnt work

also ive noticed when i let go of the gas, theres a lot of fluttering coming from the turbo. im guessing the bypass valve either just completely stopped working, or i just never noticed.

 

[ctrlz]

Do you have a hand pump to check the integrity of the diaphragm on the vacuum actuator?
Red-handled thing shown here:
http://www.amazon.com/Actron-CP7835-Vacuum-Brake-Bleed/dp/B0007VT4RC

I would look for vacuum leaks first before searching for electrical faults.

 

[AeroForce]

no
and i didnt see any vacuum leaks that i could find

 

[ctrlz]

If the solenoid (i.e. bypass control valve) is not the issue, and you have no leaks in the plumbing, the next item to swap would be the CBV itself. These have not been a high frequency failure part on our cars, but they are known sources of trouble on Volvos and Audis, particularly when boost pressure is increased over stock.

Here is a description of the failure mechanism:
http://www.quickbrickmotorsports.com/prod_cbvupgrade.html

On a Linear, your turbo is a Garrett GT 2052.

FWIW, the WIS tells you to check wiring for p0033. It specifies this as an electrical fault.
It also gives a "tip" that you can test bypass function under moderate acceleration by rapidly releasing the accelerator pedal.

 

[AeroForce]

ok so just for ****s i decided to disconnect the battery for 15 mins to reset it. everything was reset, including the CEL. i took it out for a spin and it worked 100% with no compressor surge or anything (remember that it hasnt worked for at least the past 5 days) and then it went back to the original scenario. (except the CEL hasnt come back yet)

 

[Vectorized]

My 03 Vector has been showing the same exact symptoms as well. When I do quick acceleration from 2-3 the boost gauge doesn't go past the half way mark. A restart cures the problem, but it scared me the other day when I was about to overtake a vehicle and the boost was gone. I had a CEL for a few days then it disappeared. The symptoms are sporatic and can go weeks without the problem but it still is happening.

Anyone have the part number(s)?

 

[AeroForce]

ok took it to the dealer
he said my bypass valves diaphragm was cracked and i needed a new one
kit+labor=$610 :<

 

[jlrdrony]

the 1B points are the kit

 

[BennyBlanco]

the repair kit is around $300.00 at most places.....I rest is labor

If you can't DIY, try to look for a good indy for this to save some $$$