What is the cost to repair or replace the exhaust valve on a 2007 Suzuki XL7?

Question

I have check engine light on with codes P0014-Exhaust Camshaft Position System Performance bank 1 and code P0024-Exhaust Camshaft Position System performance bank 2. Check engine light came on today on Suzuki XL7, 2007 model, however it is not driving funny or stalling or doing anything out of the ordinary. What do I need to do to fix or trouble shoot and what is the general cost of repair/replacement of the exhaust valve?