Check engine light

Have 2001 Tundra SR5 getting Hi TO temp on dash when everything is cold-Do I have a bad sensor?

 

Not following. What is a "Hi TO temp"? Is there a specific code? Which?

There are two coolant sensors - they're side by side near the throttle assembly. One is for the dash gauge. The other is for the ECU.

If your dash gauge is reading high when the truck is cold, you can test the resistance across the probes with a DMM to see if the resistance matches the FSM's values.

Just make sure you pick the correct temp sensor

If the resistance is within spec per FSM, then there could be an issue with the gauge cluster; but I highly doubt it, clusters are pretty bulletproof.

As with any electronics on these trucks, you'll want to use OEM (Denso or Aisin brand) senders as a replacement. Don't use 3rd party mass-produced brands.

Almost forgot - another possible case could be the sensor wire got nicked or damaged.