Brake/ABS light lit & weak pedal

[Johnny5]

I was in the middle of a trip when the ABS and Brake lights turn on so I kicked it out of cruise and noticed a weak brake. I still had brakes but they were not the way they were prior to the lights coming on. I basically was running down the highway at 75mph with the outside temp of -15 when the lights came on. Pulled off check for leaks,none, checked fuse,ok, fluid level,ok so I decided on a trip to the dealer. Was able to limp it to a dealer to get it checked out altho twice the pedal really went down far but not to the floor.

The dealer pulled two codes, 65 & 74 and reset and everything was fine. One of those codes I was told was "relay open" but I don't have specifics on the codes tho. Was able to run the rest of the 500 miles on the trip w/o any problems

I need to try to find out what happened especially since the brake feel was quite different when the lights cames on. To me it seemed like the ABS was activated and stay on, but in hindsight I could not tell if the ABS pump was running (not that I know what that sounds like yet)I searched on the TDR but figure it couldn't have been the typical rear speed sensor because the brake feel was not the same. Maybe it was a cold related problem? Been out in colder weather tho w/o problems.

Any ideas guys? What is the info on these two codes?

Thanx,
Johnny