This is good news for Tesla owners, and a long overdue change in Tesla corporate policy. I bought a P90D in 9/2015 and a few months later they found the main battery was defective. I asked how long it would take to get a replacement, and was told that was not how Tesla did it. They refused to give me a new battery months after I'd taken delivery of a $120,000 car. Instead, they said that they would put a 85Kw loaner battery in, and send my battery from the east coast to the west coast to be re-manufactured, then send it back, remove the loaner battery and install my battery. I said that was completely ridiculous, twice as much work for them, and please just give me a new battery. No. They explained that they wanted to keep each car with its original components.
I asked how long it would take and they said 4 to 6 weeks, "depending on how badly backed-up the remanufacturing process is". Every month I called to get the status of my battery and there was no info. Finally, at the end of 6 months I got a call saying it was being shipped, so I took my car in and they made the switch, but they couldn't release the car to me. Turned out that when they inserted it in my car they ran some diagnostics and found that it was defective in another way, as it wouldn't hold a charge. Why they didn't run the diagnostics before shipping the battery leaves me speechless.
By now after waiting 6 months I was furious and demanded a new battery versus their initial plan to re-manufacture it a 2nd time. People in the service center were terrific, but it required the service manager having to deal with management in CA and get the equivalent of a papal dispensation to have them send a new 90Kw battery. By now I was so skeptical, I wondered if it was a new unit or someone else's old battery. But, as it turned out it was indeed a new battery because it's design had changed and to put a new style battery in my car required an adapter kit which they'd forgotten to send, so that took more days.
With all that said, it's really good to hear that they finally came to their senses and are now simply replacing defective batteries without subjecting owners to any hassle.