Here's a source to support some of the above the above claims (including a link to PDF of NHTSA letter):
https://www.techspot.com/news/99079-biden-administration-car...There's some interesting context missing from the explanation too, which is that apparently the feds were consulted years ago and they said "it's fine."
The Massachusetts Right to Repair Coalition's response to the NHTSA letter:
On behalf of two million voters and thousands of independent auto repair shops across Massachusetts, we are outraged by the unsolicited, unwarranted, and counterproductive letter from NHTSA that conflicts with the Department of Justice's statement submitted two years ago in federal court stating that there was no federal preemption. NHTSA's letter is irresponsible, having been transmitted without any new evidence and after the conclusion of the federal trial, despite having been asked by the judge to participate in the court proceeding and declining. NHTSA's letter fails to acknowledge the evidence and testimony presented at the trial that demonstrated the viability and security of an open access platform. This is yet another delay tactic the manufacturers are using to thwart the will of their customers, Massachusetts voters who voted 75-25 in favor of their right to get their car repaired where they choose. The FTC, the Biden Administration, and many members of Congress have all come out in support of Right To Repair.