Interestingly enough, there's another service out there, that's only available to insurance adjusters. Mere mortals can't get access to it, but the last time I had to make an insurance claim for a totalled rig, the adjuster threw things from it back in my face when we were doing the valuation of the vehicle. This service reports any and all claims made on the vehicle thru any US insurance company. Supposedly, my rig had had at least two claims against it, which the adjuster used to try to lower the value on the vehicle--"See? It's already been in two accidents...".
Since I'd done the Carfax thing, and paid for it, when I bought it, I was a little shocked. I figured, well, at least I have a claim on Carfax, now, since I got the guarantee. Turns out that no, I didn't. Carfax only claims to have information that is reported to the DMV, not insurance claims. Soooooo... I had to research exactly what the two claims were for, and got the other insurance company to dig out the records from archives. Both claims fortunately were for under $500.00, and only one was ever paid out on, and that was for a "shopping cart ding..."
Took that back to the adjuster, in my case, and told him that he wasn't going to get away with it, soooo... we settled for three grand more than I paid for the truck the previous spring. I cannot overemphasize the importance of buying Toyota, in the first place. Haven't lost money on one, yet.
Basically, Carfax really isn't worth the money, at least for the guarantee, unless there's something actually reported to the DMV, like a total loss. If it isn't reported to the DMV for something major, it won't be on there, and then they're not liable for a dime. You'd actually have to prove that the vehicle had been reported to the DMV, the DMV had it on record, and that Carfax missed it. Which isn't so easy to do, I'm afraid. Read the fine print--I'm not sure I'll ever buy a report from Carfax again, at least the "guaranteed" one.