2011 chevy cruze that dies exhaust valve solenoid control

Question

I have 2011 chevy cruze that dies. I drove it and code 84 came on and the engine lost power so i could drive maximum 10 km/hr. Then it died so I was told to disconnect the battery for 10 minutes and it started and I drove home where it died again so i repeated and made it into my driveway. A friend said his code reader said 84 was exhaust valve solenoid control bank 2. Is this a serious costly repair or under warranty it has 104000km. I dont want to get hosed at the dealer. Thoughts? Thanks a bunch. (ps i think i hate chevy now)