Not sure, but both do point to the turbo control valve I suspect that either a hose is loose or has a break in it. One hose (red) goes to the lower section of the turbo (only reached from under the car- a PITA but do-able with some long needle nose pliers), one hose goes to the waste-gate (I believe yellow) at the top of the turbo (much easier to reach) and then the (I believe blue) other hose goes to the under side of the intake hose, past the air filter housing. I changed mine out with IPD's heavy duty TCV this past summer on both of my cars- some smoothing out was noticeable, but nothing that I would call "outstanding" as a performance upgrade.
EDIT: Just found where P1237 could be an "air-metering" code- either way, it's not a Volvo specific code. Some people with this code were having trouble with their MAF sensor. I would take it out and clean it with MAF cleaner for good measure- don't touch the sensor inside as it's very sensitive- just spray it liberally and let it air dry.
'98 S70 T5 Emrld Grn Met/Beige Tons of Upgrades Mobil-1
'04 V70 2.5T Red/Taupe Some Upgrades Mobil-1
94 850 Sedan NA Drk Blue/Tan
'00 V40 Purple/Grey Mobil-1