Ok,
Couple of you helped me out a bit looking into this, and this is a re-visit of that forum.

Here'* what I now know.

Engine gives a code 56. That'* a Quad Control Module Failure. This Quad Control module controls several functions, all 3 EGR Sensors, TCC Solenoid, Shift Solenoid A, Shift Solenoid B, and Boost Control.

Took it for a drive witha Snap-On Modis connected. All EGR Sensors, TCC Solenoid, and Boost Solenoid are working. QCM Sol A, and QCM Sol B both will read faults.... but not always.. they shift from faulty to none.

I know that Sol A controls Shifts from 1-2, and Sol B controls shifts from 2-3

Symptoms:

With vehicle in Drive. Have to rev up to nearly 3500 rpms to start moving.
With Vehicle in 2nd: Vehicle starts moving much better.
With Vehicle in 1st: Feels exactly like starting out in 2nd.

Once driving:
Can shift down from D to 2nd, and feel noticeable downshift.
Shift from 2nd to 1st: No effect.

At any speed: i.e Under 5mph, if I shift from 2nd to Drive, I can feel it shift to 3rd, and then I can downshift back to 2nd and feel it do that as well. Like it'* always trying to get into 3rd gear. Would explain why starting out in D takes so many revs to get going...it'* trying to start out in 3rd gear.

SES light will come on, usually while accelerating. Sometimes it'll stay on for a while, other times it just flashes. Never does it always stay on.


Questions:
What should the voltage at Idle be at the green wire going into the Tranny (Sol A). What should the voltage be at the black wire (Sol B).

If I hook up a voltmeter to the green wire, and accelerate with tranny in D, voltage is same as battery.

At this point, I'm fairly sure that Sol B. is staying energized. Is it then overriding Sol A, or is Sol A just not working at all?

Have at it.

From the factory manual:

1. Key Off
2. Disconnect green PCM connector
3. Key On, engine Off
4. Digitial voltmeter set to 2 Amp scale
5. Probe PCM harness terminals GC8, GC9, GC10, GC15, GD15, and GD16 (Black wire on multimeter to ground)
6. Each terminal should read between 0.4 and 1 amp.

Black wire = GD15
Light Green wire = GD16
Dark blue wire = GC15

I imagine you could do these at the transmission, but the harness will have to be connected. Do you need a PCM wiring harness pinout?

Also very carefully check the integrity of the light green and black wires between the PCM and transmission, including at the transmission harness.

Did you say you had another code with the 56?

No other codes with the 56... unless I unplug the wires from the Tranny :P

With the harness still plugged into the PCM, then you'd expect the voltages to be the same at the tranny.

Now, that said, at idle, then there should be next to no voltage at the green and black wires at the transmission.

When you start to drive, should the voltage on either increase? Sol A energized while shifting from 1-2, and then off when shifting from 2-3, and Sol B then energized?

This is the EXACT problem I am having....I guess I need to buy a multi-meter...

I replaced EGR and Boost Control already...that helped performance...but still getting a code 56..........

Just a minute, you are supposed to do the test with the green harness UNPLUGGED from the PCM. I'll have to look more into the operation of the solenoids, that I'm not sure about.

You'll find the schematics for the pinouts of the trans connectors here if that will help any:

www.williamwren.com

Click on Bonneville at the bottom of the main page, then click on the gallery link just below the list of links.

hmm so if your egr goes bad it'll throw a code 56 and its up to you to check each of the possibilities to figure out what is really going wrong?

Pretty much. That'* what happened to me a year ago with a sticky soloniod. Process of elimination for me.

With the scantool now, it takes all the guesswork out. Only takes a few seconds to nail it down.

Will the scantool be able to tell you about your EGR without running the car? Just from a key-on position

Scan tool just told me that the EGR'* were off. Had to have it hooked up and run it down the street to see that they were working.

I'm still trying to troubleshoot mine.. At this point, I'm a lil suspect of the PCM. I tried unplugging the harness at the transaxle, and according to the document I got from Shop-Key, If I place a test light (in this case a multimeter) between the main power in, and Sol B, with the engine off, ignition on, I should not get any power there... yet I am.

If I have to replace the PCM, can you tell me what ones will work? Do I have to have one from a Supercharged Bonne SSE?

www.car-parts.com didn't ask me all those options when searching for one.