To minimize the workload on Playstation Network, Sony yesterday disable code redemption section for the launch of Playstation 4 in Europe. The service was suspended just to stabilize PSN network due to high traffic on servers.
“We are aware that users are experiencing some disruption to the PSN service. To minimise the inconvenience we have suspended the “redeem voucher” functionality whilst we investigate further. Unfortunately this means that money cards, product vouchers, PlayStation Plus vouchers, PS3-PS4 upgrade vouchers and any other vouchers for digital content are not redeemable at this stage. Other PSN features such as log-in, online multi-player gaming, PlayStation Plus trial, PS Store (excluding voucher redemption), trophies, messages, friends etc. are all available.”
However there’s still a work around to redeem Playstation Plus code on Playstation 4. All you need to have is PS3 or PS VITA and a main account which you will be using on PS4. Login to PS3 or PS VITA with this main account and redeem the code, all the benefit associated with the code will carry over to all devices.
If you want to redeem a non-PS Plus code, go to official Playstation Store WebPage, Sign-In by providing your personal details, click on your PSN name and from drop down menu select “Redeem Code”.
By above two methods you can easily redeem your voucher code and link to your account and take advantage of it on PS4.