Not sure if P1633 is a Volvo code or just a generic. Sounds like you are using a hand-held scanner maybe?
The 1181 and 1171 point to a possible manifold vacuum leak or a faulty 02 sensor or leaking in injector? The fuel delivery system is not happy for some reason and keeps re-adjusting itself. Maybe get in there and check for loose vacuum hoses, dirty MAF sensor, etc.
The 1633---not sure if that's a good number---but I've read that when you translate it into a Volvo trouble code it suggests the ABS module is flaking out. I think if you did a "deep scan" with the Volvo-specific tool you'd come up with some verification for these codes.