Check Engine Light on S40: P2402

Hi everyone.

Check Engine Light came on last night on my 2007 S40 2.4i with 68K miles on. I had the OBD II scanned with Actron OBD II AutoScanner and got P2402 code (Leak diagnostic unit, pump; Leak diagnostic unit, heater pad). After hours of researching I decided to seek help on this forum.

Does anyone know how to resolve this problem? I tried tightening the gas cap - CEL is still on. Is it safe to drive the car with CEL on? I need my car on a daily basis, so I will have to drive it until I can see a dealer.

Thanks!