Call up R&R I hear they have fantastic deals....
On a serious note most people replace all four CPS at the same time.

check this out: http://www.m5board.com/vbulletin/e3...9-m5-e52-z8-discussion/99962-knowledge-base-peake-codes-e39-m5.html#post1090451
12 is Map controlled thermostat actuator
25 is “PreCat oxygen sensor heater control, Cyl #1-4” you can get them on amazon for like $50

 

The first step is to make sure what the codes actually are!!!

 

bmwMcrzy,
Heres what i found online, Peak code reader is different from the code reader i have.

P0012 - Camshaft Position Timing Over Retarded Bank 1
P0025- B Camshaft Position - Timing Over-******ed, Bank 2
P0172- System too rich Bank 1

not sure what to do here.

 

I just don't get how your VANOS issue led to a head value gasket needing to be replaced and now your CPSs?
Saturday I'll be heading to SuperCar Saturdays in Bolingbrook, I can swung by your place again if you need an extra pair of hands.

 

vanos seals were bad and we broke a spindle taking it out, so we had to pull the valve covers off to pull the old spindles out and send them off to get fixed, then we had to time the motor after re-insterting the gears.

 

What reader are you using? Those are very generic codes and I am skeptical, but I know what they mean. 172 is rich on bank1, you may not have had the occurrence since you cleared and drove. The 12 and 25 are the solenoids themselves one on bank 1 and one on bank 2. My experience with those codes are they are triggered by something that I don't think BMW designed and cars that have had those or the other bunch get totally different codes when read with Peake or other more specialized BMW readers. The out come or approach to repair is the same however. Solenoid maintenance covers everything that could be wrong with the board so you are good to go.
P0010...."A" Camshaft Position Acutator circuit (Bank 1)
P0011...."A" Camshaft Position - Timing over-advanced (Bank 1)
P0012...."A" Camshaft Position - Timing over-retarded (Bank 1)
P0013...."B" Camshaft Position Actuator circuit (Bank 2)
P0014...."B" Camshaft Position - Timing over-advanced (Bank 1)
P0015...."B" Camshaft Position - Timing over-retarded (Bank 1)
P0020...."A" Camshaft Position Actuator circuit (Bank 2)
P0021...."A" Camshaft Position - Timing over-advanced (Bank 2)
P0022...."A" Camshaft Position - Timing over-retarded (Bank 2)
P0023...."B" Camshaft Position Actuator circuit (Bank 2)
P0024...."B" Camshaft Position - Timing over-advanced (Bank 2)
P0025...."B" Camshaft Position - Timing over-retarded (Bank 2)

Best guess is that you have decayed filters stuck in the solenoids. Search solenoid maintenance and see the sticky DIY thread. A= intake B= exhaust.

 

this?

http://www.m5board.com/vbulletin/e3...lletin/e39-m5-e52-z8-discussion/202759-vanos-solenoid-maintenance_full-diy.html

 

Yes, but you really only need a 9v battery, 8 D batteries might just be enough to pop a MOV depending on how long you leave it connected and its connection to the board. I have not calculated the output however, but less is more when activating the noids as long as it is enough. 2.5 watts is enough juice to activate the noids.
This may give you an idea of what you are up against.
http://www.m5board.com/vbulletin/e3...discussion/203404-how-clear-out-stuck-solenoid-wont-clear-vid-pic-attached.html
The 172 could be caused by this but you may have a small leak in the IAC piping, but deal with it after.