Samsung Galaxy S3 wifi battery problem


Hey guys I recently encountered this problem where my Samsung Galaxy s3 starts picking up wifi or alerting me that its picked up wifi and it seems to be draining my battery rather quickly. ive done pretty much everything to conserve battery life. Ive had the phone for about a month and have had no battery problems until now. I did however update a few days ago. people are saying to try to dial #0011# however when I try it says invalid MMI code,, what does that mean? Why doesnt it go through?