My cars service engine soon light keeps coming on when I am slowing down, all the way from 70 to about 5 mph. When I come to a complete stop it turns off. So I checked the codes myself and code 56 comes on which is for the boost control solenoid. Do any of you have any idea what could be causing this. My supercharger is not rattling or making very much noise.

I'm pretty sure your boost control solenoid is shot, but I'll check in the service manual later.

Here is your solution:

http://www.bonnevilleclub.com/forum/...pic.php?t=2066

Yeah most of the time when that code comes up its shot.... :?

I was wondering if an intermittent code 56 (1992) could also be showing a TCC solenoid problem?
I know I have a TCC problem.
Thanks for any replies
Brett

Does your ses light come on mainly during deceleration?

I just noticed the SES today but it seams to me that it comes on some were in-between, will go OUT when accelerating or decelerating. I have to check if all the boost is there but I think it is. I need to drive the car some more.

What I really want to know is if the Quad B drivers also control the TCC solenoid and the EGR.

My TCC is not working well at all. I have to use the brake a lot to stop the TCC from trying to lock up going up a hill. The next time the code comes on I will keep the TCC from locking up and see if that stops the code from coming on.

Maybe the code 56 is trying to tell me the TCC solenoid is the cause of my transmission problems in the first place but the SES just started to come on, and I have had this Transmission problem for 1½ years.

Oh Well

So now the Boost solenoid may now be going bad to. I wonder what will be next?

Your symptoms are not representative of the boost control solenoid going bad. However, yes, that code means that there is an improper voltage level being detected at the TCC or the EGR.

If it is the TCC, it won't apply or it will have harsh engagement.
If it is the EGR, you will have poor driveability if it is stuck open all of the time.

If it is the TCC, check the wiring to the transmission and see if any of the wires are burned anywhere?

Do you have any other codes?

Only a security code (58 )
Hopefully I will find out more today about the boost.
And check wiring.
I KNOW I have a TCC problem. So I am almost sure that’* where
The 56 is coming from.
I saw somewhere that they can replace a TCC solenoid for 150 to 250.
Is that true?
That’* a lot cheaper than a rebuild.

Waitaminnit here: Keep in mind that the TCC solenoid only does what it'* told to do; it doesn't make any decisions itself. It sounds more like you have some funky control system or sensor problem that'* telling it to engage at the wrong times. If it engages properly when it'* told (rightly or wrongly) to do so, and disengages properly when you step on the brake or coast down below about 45 mph, then your problem is not with the TCC solenoid itself, and replacing it will not make any difference.

(For the record, I don't believe a faulty TCC sets any error codes, either.)