I have a 1992 SSEi that I think, from reading here and getting a code 56, has a problem with the BCS.
Can someone tell me what part I should buy, is it the part that goes under the name by-pass valve in different GM parts sites? (about $20-$25)

Also I would like to know if a BCA+BCS from a -96 SSEi fits a -92 SSEi?
I see that they have them listed 92-95 and 96-99, what´* the difference?

/Mike

I changed the BCS on my 2001, and I am sure the part number is different than yours, but it is called a "valve */c bypass". For mine, the dealer wanted $45 and I got one off Ebay for $25. The part number for mine is 1997244. Call the dealer, tell him you want to check price and availability, and find out what the part number is for yours. If it is the same (I highly doubt it is) let me know and I will send you a link for where I bought mine.

If the dealer gives you a significantly higher price than $45, he is probably giving youa price for a boost control actuator.

I know that there are different part numbers for the 92-95 and 96-99 but as I found a used BCA+BCS from a 96 I would like to know if it´* possible to get it to fit or just what it is that is different.

I need to order online as I´m from Sweden (forgot to tell, sorry) and those parts have never been in store here.
There are not many newer Bonnevilles at all over here...

/Mike

Aside from the code, what makes you think your BCS needs to be replaced? Do you have a boost gage? If you are doing 80 KPH and do a wide open throttle acceleration (foot to the floor) what boost pressure does your gage show?

243 would be the DTC for a BCS circuit error. Can you reread the DTC and post the code. A code 56 doesn't make any sense.

Do you have any other codes along with the 56? Do you have any other drivability issues?
The reason I ask is code 56 is a QUAD DRIVER code
Think of a QUAD DRIVER as a circuit breaker. There are other circuits the pcm monitors that could set this code. If you have other codes or drivability issues you may need to start with those first.

The threads I´ve read here regarding a code 56 is that when driving and leting the gaspedal up the Service Engine Soon lamp lights up and then it goes away a couple of seconds after I hit the gas again.
This failure is cured by changing the BCS by others in this forum.
Code 56 is Quad driver "B" which controls the TCC sol. Purge control sol. EGR control sol, and the check engine lamp.

Also after getting the light the first time after start I only get about 5psi of boost at wot.

/Mike

Do you have access to a scanner? You can look at BCS and other parameters like EGR and trans data. Then you can isolate what going on.
The scanner should measure BCS as a %. The computer turns the sol on (there by opening the bypass valve.) the % should go lower. At idle it should be at about 100% and under boost conditions it may go as low as 0%. Have you tired to unplug the BCS and see what happens? Be carful if you try this so you dont overboost and blow the engine up.
The other thing you could do is pull the PCM connectors and pin out the solenoids on that QDM.
If you want to try that I'll try and get you a wiring diagram

Please take this as a comment, and not expert device, but I think 5 to 6 psi boost on your car is normal.

5 psi of boost is a little low, but that depends on your elevation. You should see around 6. Stock boost gauges tend to not always read right. Watch the lever movement with engine running and then give a throttle snap, does the lever move fully? If so, the BCS is fine.