hi tech i have a volvo 850 turbo 1995 and my check engine light is on and i retreive the codes from the engine
compartment and this is what i get and if you can tellme how to fix and how hard it would be.

codes:
153
212
121
231
436

thank you..[X(]

 

I would say you need front and rear O2 sensors.

It is not all that hard to replace them.

ALso look really good for vaccum leaks.

 

thank you an i would start checking for prices