Consumer Reports data on car reliability is demonstrably useless. No idea why anyone bothers with its junk surveys. A few years ago Toyota had serious issues with its cars. So many serious issues that insurance companies were contacting NHTSA and telling it that it needed to investigate. What did CR show? Absolutely nothing. No idea how they collect data or whom they collect it from, but when every insurance company in America sees huge issues and CR sees nothing, you can be confident its surveys aren't measuring anything real.
I greatly prefer TrueDelta. You get the raw numbers and, if you like, you can drill down and find out exactly what was fixed. On TrueDelat the only MY Volt that gets low grades is the 2016 MY, and that is not available to the public because of a small small sample size. Other years are good to great. This includes the 2017 MY, which has a reported 8 problems per 100 vehicles.
I have been reading the posts here for about 12 months (since I bought my 2017) and I was disappointed for many months to see so many folks having a litany of issues.
This is really what happens when you have a biased sample size. As noted above, TureDelta shows the 2017 MY as having 8 problems per 100 vehicles. That is about as good as it gets. (The 1026 MY Corolla has more). However, when you have thousands of members, and members who have problems post about those problems, you end up with "a litany of issues". I don't see any serious systematic issues with the second generation Volt after GM fixed the engine issues and software with the 2016 MY. That's not to say owners won't have serious problems, but I don't think the numbers suggest a major problem.
As an example of how sample bias works, with the first generation there was a problem with a small number of ball cages. The car would sound like a table saw when you hit the brakes. Based on postings, and ignoring background numbers, some forum members were convinced the failure rate was in excess of 10% or 15% (the fact that the repair wasn't always properly done -- necessitating a second repair -- didn't help). Turned out the rate was something .01%.