I cant get a key less entry to work for my car.

Question:
1995 Volvo 850 Turbo ,I cant get a key less entry to work for my car. I tried turning the key 5 times on and off and then trying to make it so the light on the dash starts blinking

Answer:
Make sure you have a new battery the remote. close the door turn the key 5 times then push a button on the remote and hold for a few seconds. then turn the key off and try the remote. if that doesn't work you might have a bad remote. is this a new remote? the light will blink when the alarm is set. that can be done with the key in the drivers door.

I have a 1996 850 Volvo. What does the code 172 mean and what repairs are required?

Code P0172 is for system too rich. This can be a problem with on O2 sensor, fuel pressure, leaking injector, cylinder misfire. It will require a little more diagnosing before a specific repair can be determined. It may also be caused by a vacuum leak.

P0172: System Too Rich (Bank 1) - From a quick search, Tech has said this indicates a vacuum leak. Also, see this thread which sounds similar to your issue: http://www.volvoforums.com/m_57903/tm.htm.