Factual error: The Akula class submarine is an attack class submarine, not an SSBN (Missile Carrier).
Plot hole: Using an EMP to disable the security at the base would render anything electrical useless, computers, cars, cameras, anything with a micro chip in it. Firing a EMP directly under something you want to steal like a submarine is completely stupid - Cypher would know this.
Plot hole: The nuclear codes are stolen and the Russian guy holding them was let go by Dom. He would contact his government to let them know and the codes changed. Cypher would also know this so her plan is flawed.
Continuity mistake: Near the end, the Russian chase vehicle fires a grenade at Hobbs' vehicle. The tube on the top far right is used and can be seen open. When that same vehicle goes for the second shot at Hobbs, the tube that was used before is unused now. When Dom hits the vehicle shortly after that there is a very close shot that shows that despite having just fired another round the array of tubes is again unused.
Factual error: When the EMP goes off - apart from the obvious like the ridiculous shockwave...it causes the big gates to fall down. This is a unsecure security principal called "Failing open." I highly doubt that a secure military station would "fail open." Instead if would fail closed - ie if something went wrong then the defense systems would default to being closed and impenetrable.
Factual error: When the heroes are trying to shut down the submarine's missile launch, the keyboard in the control center is in English characters.
Factual error: At the end of the film where the gang are trying to outrun the submarine, it should be noted that submarines cannot travel much faster than about 40mph when submerged, let alone above water/icebreaking. Yet it is shown at least keeping pace with the Fast and Furious heroes.
Other mistake: How did "Cipher" get in her car and drive off without replacing the fuel linkage and putting down the hood?
Plot hole: There is no way that Dom could have organised the meeting with Shaw's mum or contact the guy from Cuba or his two friends from Brazil that were in Fast Five to shoot Shaw, or to organise Shaw and his brother to be kitted out with wing suits and board the plane. Nobody or Hobbs must have been in on it for it to work.
Factual error: Roman is completely submerged in ice cold water and is trapped in his car when pulled out, he would be suffering from hypothermia by the end of the chase but is completely unaffected by it.