It Is difficult to give you an exact estimate as to what it will cost to repair this. For example on the P0115 code this means there is an open or short in the EFI water temperature sensor circuit. This could be anything from a bad sensor which would cost you approximately $60 in parts and one hour in labor at about $100 an hour would be a total of about $160 to repair. However if you have an open or short in the wiring somewhere replacing the sensor would not resolve this code. On the P0401 code this means there is insufficient flow in the EGR valve system. You need to apply vacuum to the EGR valve and see if the engine stalls or idles rough if it does then this means something in the control circuit like the vacuum switching valve or possibly vacuum line is not on or is broken. The vacuum switching valve itself is about $75 +1/2 hours in labor. It is unlikely that the EGR valve is bad. They rarely ever fail on this. The only other possibility would be is if carbon gets buildup in the intake manifold where the exhaust gases are supposed to travel through for the EGR system then the manifold with may have to come off in order to clean this. If you apply vacuum to the EGR valve and it does not stop or idle rough this usually means the passageway is plugged with carbon.