2004 Aero 9-5 low boost :(

[Digger]

Digger, can you link me to the service bulletin, please?

What do they mean by "control function"?

Thank you very much, I appreciate your time!

Would hook you up if I could but I got the WIS on cd, not from the net. Guessing from the line art showing the wire harness to wiggle that the control function comes from the engine controller. The WIS expects you to have all the tools referred to and do what it tells you to do, then answer the question by clicking on yes or no to get a new set of instructions to follow. OK for simple hand tools, not so good when it wants the Tech 2 that you don't have, to run a test you can't run and provide the answers you don't have. With that the WIS doesn't tell you what's being tested until it tells you what to do next and if you answer yes to see where it goes next, you can't go back a page to see where you would go if you'd said no. Interactive manual might be faster for the big shop with the expensive tool, but the old fashioned shop manuals with printed flow charts were better for the guy without.

You can't test your engine control, or slip in a good used one to see if it's a problem without the tool, but you can disconnect your battery for 15 minutes to put the whole system back into learn mode and see if it changes your boost. Without a vacuum pump and gages you can't over pressure to test, but you can disconnect the vacuum line to the bypass diaphragm, move the arm to squeeze out all the air and plug the line with your finger to see if the thing holds vacuum. After that you can start wiggling wires, you might not know what you're finding, but if you do find something you will know where you were when you found it and it's amazing what you can find using what you have at hand. Using the bypass diaphragm as a vacuum source you can test every vacuum line and valve in the car, it won't be quick and you won't know how much vacuum you're holding, but you will know when you're not holding vac.

[swisssaabist]

guys sorry for my ignorance but what is seafoam ?

[Digger]

guys sorry for my ignorance but what is seafoam ?

Sea Foam is a brand name for a cleaner that removes varnish, cleans out carbon and doesn't dissolve rubber.

[Kazamario]

Digger, you are a wealth of knowledge, are you a Saab Tech?
Thank you so much!

[Digger]

Not a Saab tech, grew up in a family filled with car dealers and when I was big enough to push a broom started sweeping out the shop and hanging with the mechanics. Still learning my way through the Saab specific systems. Good portion of what's under the Saab hood is also under the hood of a GM car and for a good portion of this the Saab is just a car.

[Kazamario]

Excellent! I know my cat is clogged, what's the best way to remove it?

[Digger]

Remove using an air impact and have a torch ready to heat the nuts to glowing red because we live in road salt country. More often than not you burn them off when you don't have to save the studs.

You have a couple of good choices for replacement CAT's on an OBD 2 system, new CAT assembly, re man CAT assembly and then there is the 9 times out of 10 not worth the effort even when you have a pipe bender, wire feed welder and hoist and a replacement which I won't mention as the direct fit parts are still available.

[Kazamario]

@Digger - Just looked underneath, the bolts by the resonator are corroded af. Torch time. Thanks for all your help!

[Digger]

Turbo's don't like back pressure, they do need a little bit or they don't spin up right, but anything more than the little bit is too much and a turbo that can't exhaust can't boost. A plugged CAT can be a plugged or disintegrating core, it isn't good for the exhaust system, but won't cause the kind of problems that a busted or melted core will, so if your CAT is rattling with lots of chunks better bang on the resonator to make sure it's not filled up with chunks that can plug you up again.

[Kazamario]

**UPDATE** - My cat disintegrated and clogged my exhaust. Replacing the exhaust solved the issue