Fault code P0172 Adaptation. Rich Mixture

Hi All
My 1997 9k CSE keeps throwing out the p0172 rich mixture code, i was wondering if there was a common fault for this as my last 9k did exactly the same thing with it. what happens is when i clear the code with the engine running the code doesn't return, as soon as the ignition is switched off and back on (but not started) the code returns, this seems as tho it shouldn't be able to happen as how can you have a rich mixture before the engine has started, making me think that it might be a common fault bringing it on.
if anyone knows what diagnostic procedure to use/figures i should be getting or even better i have a little code reference book from saab and it tells me to look in service manual 2:7 page 136 (my 9k is the 2.0lpt variant) so if anyone can scan a copy of the relevant pages of the book and post them that would be really cool.
thanks in advance for any help you can give

Hi
I put P0172 in here.
Saab P0172 OBD/DLC Error Code - System Too Rich
OR
P0172 | CAR OBD CODES
Excuse my ignorance for asking.
Your 2.0Ltr low pressure turbo . What engine is it? Is it a B204E and does it have a distributor and HT leads
or a Di-pack. It would me so I don't give you non relevant info . I may have some info listed under something completely different, but relevant to the engine type or ignition system.
Hope this helps.
Dave

Thx for the reply, That car failed its mot quite badly at the beginning of this year so no Longer need this info, thanx for your time. :D

Ouch.
Sorry about that.
Every day is a school day, they say. Whoever they are.
My lesson is to pay attention to thread dates.
On a plus , some info is there for others.
Ttfn.
Dave