2012 Prius with 10K miles. One of the features I really like over the '06 Prius is the ability of the cruise control to hold the set speed on downhills (until the battery fills up and it switches to compression braking "B" mode, but that's a different topic). After taking it in for the 10K mile service, it no longer engages regenerative braking on downhills with cruise control set. This is on the same hills where previously it would hold speed. Did Toyota do a software upgrade that disables this feature?
My 2010 Prius is approaching 160,000 kms (100,000 miles) and the regen braking in cruise control is still working the same as day 1. I suggest you have a problem and should take it back to the dealer.
We have no hills here, but going downhill in a tunnel, my 2011 Gen3 just stops the ICE en speed goes up, over the set speed. No braking.
Cruise control will use regen braking to attempt to hold the car to the set speed, however, some hills are too long or too steep and the car will speed up. I also find that it tends to over-compensate on the uphill on long hills and tends to go over set speed for a short while once the crest is reached. Owner Beware.
