I recently asked Toyota for the number that turns on the A/T High Temp light on my 2013 V-6 Tacoma with the tow package. I have a Scan Gauge and I have seen as high as 230 on the Trans Temp so I was curious. Here is the answer:
Dear Terry Tubb,
Thank you for your follow-up email.
We apologize that the Owner's Manual does not include the temperature in which the automatic transmission oil light will illuminate in your 2013 Tacoma.
If you are towing with your vehicle, the automatic transmission oil temperature light may illuminate at 302 degrees. If the light comes on, it indicates that the auto transmission fluid temperature is too high. If the light flashes, it indicates a malfunction in the auto transmission system.
For further evaluation, information and assistance, we recommend you contact your local Toyota dealership.
Toyota Customer Experience
Now we know.