Q: I recently replaced the power steering pump. I notice the fluid was leaking out of the lid. My check engine light came on as well.

I recently replaced my power steering pump. After five hours of driving I notice the power steering nose coming back. I checked the reservoir and it was empty. I added more, turned the engine on and watched to see if I could see a leak. It was coming out of the reservoir cap. I took it back to the mechanic he said it wasn't leaking from there, he said it's my rack and pinion. Also on top of everything my check engine light came on the codes are P0174, P0171. So I guess my question is what is going on with my car it all started with replacing the power steering pump.?

My car has 141000 miles.
My car has an automatic transmission.