what do the codes mean? anyone?

Ok thanks to T5-ones i have a code reader and have taken the codes form my car now i need som advice on what they mean, they were in order 0107 which says its manifold absolute pressure/ baro pressure circuit low input 0171 system too lean whats happened in the past xmas time i has a stutter and judder i replaced the fuel filter and the plugs and it went away the ecu light dissapeared but i needed to read the code, i went to afgan for 4 months and while i was away my dad neglected to drive or even start my motor for the first 2 months and i guess the batter deteriorated and when jumped it he drove it it conked out after about 1 mile and would not start the battery has been changed and it runs fine, i more wanted to know if there is any thing else sinister happening from the codes i pulled its a 2001 2.0 s40 t4

P0107s probable causes are Wiring short to earth, Manifold Absolute Pressure (MAP) sensor, BARO sensor or ECM. The p0171 codes probable causes are Intake/exhaust leak, Secondary Air Injection (AIR) system, Mass Air Flow (MAF)/Volumetric Air Flow (VAF) sensor, fuel pressure/pump, injector(s), Heated Oxygen Sensor (HO2S). If you have reset the ECU and there are no codes in there any more then dont worry about it. If the ECU light comes back then its a hard fault.

every thing was fine yesterday took her for a blast but went out this morning she started but...... wont idle properly and there is very little throttle response any ideas?

the barometric sensor if faulty wont cause any problems in the uk, it merely defaults to a sea level pressure figure(14.7) the only time you would notice anything if you were at high altitude and the eec wouldnt increase the boost level to compensate, its located on the rh side inner wing just behind the headlight adjusters

cheers mate thats one off the list. i have now bought a haynes manual but where it says the MAP sensor is i cant find anythng there is a load of plugs but hee haw else apart from conduit and plugs, i cant see any vacum hose? Haynes manuals being as ambiguous as normal

I have found a page that details the codes specific for volvo, and its states that 107 is Boost pressure signal too low, what sensor is this then? or is it somthing else or a leak?

yeah thats what am doing but i cant find the map sensor to see if its dirty or has loose wiring haynes dont show it and i cant find it, most prob because i dont know what it looks like lol!!