My son works at a Caddy dealership here in Fla., he recieved a service bullition last week for installing an "auxiliary vacume pump" on 2005-2006 caddy's with 2.8 engine.
It's for hard brake pedal in cold start situatons at altitudes between 4000-6000 ft.
Oh!..........................the part number you say?
That would be p/n 15837490 , my son said it was under 100.00 his cost?
After I payed allmost twice that for a used one! #$%#$^&$*@
I have a good mind to buy one just because.......?
Anyway I hope this will help solve low vacume problems at a reasonable cost for someone?

T.C.

TC...do a double check on that P/N. I did a search on GMPartsDirect and didn't get any results.

Thats the correct number 15837490, mabe it's to new for parts direct?
I have a feeling it's a dealer only item and I wouldnt look for the price to stay at under 100.00 even for a GM employee.
I would try to find a "buddy " that works at a local Caddy dealership.
I had my son do a price check on one and he said it was around 85.00 so I figure 100.00 shipped?
The service bulletin is number "06-05-22-003" the date is May, 2006
It is called "auxiliary vacume pump kit" P/N 15837490 thats taken rite off the Bulletin so I know it's correct.
Hope this helps?
T.C.