Need some input and ideas.

Was driving my '93 SC400 (171,000 miles) today and after less than one mile, the CEL and TRAC light came on, then the temp guage started rising. Tried to go less than one more mile to get to a place to leave the car, but stopped due to the high temp reading. Coolant was in the engine bay due to the overheating. Installed a new radiator less than 90 days ago and car was running perfectly since the new radiator and early in the day. Tried to get a code from jumpering the OBD I connections, but got no readable codes.

Any ideas? Will be having the dealer look at it on Monday. Just curious as to any ideas before it gets there.

Thanks!