[SwissXC90]

You definitely want to get VIDA, the factory diagnostic system. Readily available, and it will be like all your Christmasses have come at once as it tells you everything you need to know to work on, disassemble, reassemble and fix the car. Including all parts lists, and functional and technical descriptions. It's a godsend.

The later models after 2006 are very reliable

The sound system has 3 x levels:
Basic - not often seen, no external amplifier
High Power - with external amplifier
DynAudio Premium audio - with even better amplifier and more and better speakers (but check each speaker, they can blow)

Go for a system with built in Nav and Phone and then you can easily add the Camera: but programming is required.

I have a MY2009 R-Design with High Power audio and Nav and Phone and Backup Camera, all original Volvo. And rear seat entertainment (DVD player). It's brilliant. Try and get the DynAudio Premium system as well. The subwoofers were no longer fitted from 2006, so don't expect to find a subwoofer. there's more than enough bass anyway.

Watch for leaking sunroofs, they make the carpet wet underneath. The car needs to be bone dry, avoid anything that shows signs of wetness, especally as it can kill some electronics.

Watch for creaking, knocking suspension - more prevalent on >80,000km

Watch for lack of regular service, especially on a diesel. Make sure the inspections have been done regularly and all is present and correct in the service booklet.

The more switches fitted to the switch row (under the climate control), the more options you have. On my car, I have 6 out of the 7 switch positions used for options.

A useful option if you live in a hot area is the Rear AC (look for the switch) which is for the 3rd row of seats

In the UK almost all XC90s come with alarms, watch for an Alarm Service Required which is normally a failling backup battery in the siren

Look also for Volvo On Call (button under the hazard switch, which can be a lifesaver in an accident

Check the 3rd seat row comes out and clicks into place without any jamming. Check that the owner kept the car clean and tidy, you'll often find muck under the 3rd seat row.

Watch for any diagnostic troubles codes stored in the vehicle, you can retrieve the status (codes stored or not) on the instrument cluster without any tools. Exactly what codes are stored requires tools such as VIDA.

Watch for a good activing parking brake

On my 2009 XC90 in 2 years of ownership I've done the following:
2 x regular services
1 x tough vehicle inspection which failled on parkinng brake, requiring full renewal of discs and pads of the rear braking system (rusted through lack of use. Bad!)
Replacement of front brakes (worn, end of life)
Replacement of lower engine torque arm (worn out, end of life)
Replacement of transmission oil (preventative, precautionary, at 125000km)
Replacement of Xenon bulbs (old, end of life)
Replacement of 2 x minor taillamp bulbs (old, end of life)
Replacement of starter battery (old, end of life)
Replacement of one trim panel clip (was missing)
Replacement of batteries in the remote controls (old, end of life. My car has 3 x remote controls: nav, stereo, DVD player)
Replacement of motor cover rubber bushing (fell out, lost)
Fixed a rattle in left rear door speaker area causing vibration on some bass notes
Updated sat nav maps to current 2017/2018 maps
Cleaned injectors electrical connectors (causing very random misfire on cylinder fire)
Cleaned motor bay with a toothbrush, looks like new (was required for inspection)

One fault on my car still to fix:
Left hand wing mirror folding motor is jammed (currently I have disconnected the motor)

I monitor fault codes every month or so to see what is developping, not every logged fault code causes a warning light, but very useful over time to see what is happening. I use VIDA to do this and keep PDF printouts of vehicle fault status for later reference.

My car now has 127,000km on it, over nearly 10 years of life.

Great car, very reliable, only minor problems apart from my biggest surprise being the parking brake at inspection time.