How do I pull '09 V70 OBD-II codes?
 

I currently have a "check engine" indication on my dash, but car seems to run fine, and fuel mileage is normal, but I want to make sure nothing is going on that I need to address. I have a code reader (nothing fancy, but has worked on other vehicles for years). I usually have to turn a key in to the "ignition on" position to generate and read a list of faults. Since this generation doesn't have a traditional ignition key switch, how do I get the code to show in my reader?

It'll work with the engine running.

2009 V70 is P3, not P2

If you dont have an OBD2 reader, you can stop by a big box parts store (Autozone etc) and most will lend you a scanner. Under the dash on the drivers side you will find the connection port - kind of looks like an old school printer port (1/2 inch by 3 inches say) plug the code reader into that then turn the ignition to position 2 (engine does not need to be running) which will power the reader and allow it to talk to the computer(s). use the reader menus to read through each of the codes. Have a pen/paper handy so you can write the codes down. Most readers will show the standard "P codes" ie P0301 = misfire cylinder 1 etc. Some will interpret the codes and give a possible solution but best to do that research off line since some of the codes are proprietary (ie specific to Volvos). Once you read all the codes, the scanner will allow you to erase the codes. This should reset the CEL. Note that depending on the true fault, the codes may immediately reappear or it may take 50 miles or more of driving for the code to return. During that period, the codes will be in a pending mode since some codes average data over time (thus if you cleared codes you may need to do a drive cycle to complete the reset before getting an emissions test done...). If you prefer, you can also buy your own code reader. I keep a $30 reader from Harbor Freight in my car that's good enough to check the P (powertrain/emissions) codes as needed. The more expensive readers can do things like ABS, chassis, SRS etc each which are their own code sets, and some can do e-brake resets. Those will run $100+.