Have seen the P0022 one of two times, P0025 ... probably more that 15 times.. time has come to repair it.
Googling- I found some contributions as to what the reason could be. In the simplest case, the repair comes down to replacing the camshaft adjustment solenoids (or magnets) on the left side (the Bank 2 or driver side) of the car.

If you get the warning P0015 or P0012, the issue is the same, this time on the right side (Bank 1 or passenger side)

In any case, the solenoid it exactly the same - the P/N 272-051-01-77, they all should come with a rubber seal.

You can buy it at MB dealership for some $100 (just one of the solenoids) or somewhere else, where you get genuine parts. I bought 2 on EBay, hoping that they are genuine... for total $50.

The repair...

- Bank 2 (passenger side)

The replacement is very easy, than both solenoids are exposed - not covered by anything as I now believe. Since I replaced both on the other side, I did not really examine the right side, but from I remember, the are exposed.
That means - 3 screws per solenoid, the kinda a star screw, for which you will need the E8 nut or simply 1/4 inch ring wrench, then you need to reconnect the cable connector - which is tougher than the screws.

- Bank 1
I saw a video on youtube in which a guy on the E350 engine (also M272) removed the power steering fluid reservoir to replace the exhaust camshaft solenoid (causing the P0025) and then, removing the oil cooler (the silver box) to replace the intake camshaft solenoid (causing P0022). This was impressive work - lot of work.

Preparing for this I already ordered the oil cooler gasket... then only, I decided to try to exchange the solenoids without removing anything first.

I works surprisingly easily, I unscrewed and removed all 3 screws for the exhaust solenoid. The key to unscrew the screw behind the reservoir was a simple 1/4 inch ring wrench working on the T8 - type of screw. In fact I used the wrench on all the screws, without the T8 nut.

There is some patience and "finger" work required playing with this screw, but it is definitely worth it, rather the removing the reservoir.
The same - 20 minute later - with the intake camshaft solenoid - exactly same story. No problem at all, no need to remove the silver cooler at all. So, just few minutes later I canceled the order for the seal!

The difference here - I had to unscrew the camshaft position sensor ( one screw) to remove and replace the solenoid.

I wonder now, was the gap that the MB designers left between the solenoid and the reservoir and/or the cooler merely an accident... or was it perhaps design... - to make it easy for us.. damn, the Germans!

I hope this will help someone, I wish for one, I'd have found such info before. Please place your experience after resolving an issue as well, not only the questions before!



Greetings
OKinChi