I had a similar brief squeak on startup when cold. I replaced the belt with an aftermarket one from my local parts store. sueak was gone, but came back after about 8k miles. Returned the belt and bought an OEM toyota belt. Squeak went away and has been trouble free for almost 50k miles. I'd start with a genuine belt before checking anything else.
Anybody know of a recommended interval for changing the belt. I didn't see anything in the manual about it. I also didnt see any indicators by the tensioner that let you know if the belt has stretched (i have owned other vehicles with no recommended interval for changing belts, but had a gauge by the tensioner to indicate if the belt had stretched and needed to be replaced).
