hi everybody picked-up 05 xc90-v8 with error codes p0012 & p0022 intake camshaft position timing over retarded {bank 1} & bank 2. never worked on v8 but sounds like timing chain changeout maybe, has anyone done this ,is it diy job or dealer. any tips does anyone have procedure or know where to find it. any help will be appreciated. thanks

Sounds like the solenoids are sludged up and no longer working. Or the oil level is very low. Not a timing chain problem.

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Keeping it running is better than buying new

thanks for the info my next question is where are they located on this engine, can they be cleaned??

On top of the block, just to the rear of the timing chain cover. All four of them have an electrical plug. The oil passages can be cleaned with carb cleaner. FCP has them for around $140 each:

https://www.fcpeuro.com/Volvo-parts/XC90/Variable-Timing-Solenoid/?year=2005&m=855&e=2016
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Keeping it running is better than buying new

thanks for info. you seems 2 b very knowledgeable about v8.I think I was able 2 locate sensors. 2 at oil fill and the others in back under intake, looks like I have 2 take it off. they're held by 10mm bolt, after that r they just pulled out??? and cleaned. it there a way 2 test before replace. 2 save time and money which is tight. while I got u is there any repair manuels out there??

At a minimum, you will need gaskets to put them back on. Repair manual? Perhaps in VIDA. The V8 is not a Volvo engine, Yamaha 4.4 V8 , but that is a rumor.

You could clean off one and see if the error messages change...
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Keeping it running is better than buying new

on v8 where ae they located

Never having seen a V8 engine, take a look at this diagram that shows all 4 of the sensors:

https://www.volvopartswebstore.com/products/Solenoid/10925620/30684282.html

The problem is that the diagram does not show if they are under the valve cover or extend through the valve cover. They are on the front of the engine, passenger side.
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Keeping it running is better than buying new