Any electrical signal lost on a Drive-by-wire system, can trigger a Limp mode.
Does weather, or water play a factor?
Did the shop do a full Power down on the EBCM?
We have seen both broken signal wires, and bad electrical connectors on Electrical Controlled Throttle bodies.
See AF
www.automotiveforums.com/vbulletin/showthread.php?t=974347
AF
www.automotiveforums.com/vbulletin/showthread.php?t=975140
Yes - If a Limp/Fail safe mode is triggered, it's a 35mph-70mph accident in rear waiting to happen!
If any Automobile manufactures are interested in a safer solution for a Safer Drive-By-wire system, please conatct me ASAP.