This piece that plugs into the receptacle that you see below the two wires is missing. Mechanic does not know where it is after replacing engine. Any idea what it's called? Fits into coolant sensor receptacle....If I knew what it is called i could perhaps locat

e a replacement...

 

Your missing the connector that should be at the end of the two wires? If so Toyota calls it a "connector joint wiring harness".

The connector shapes and number of terminals are different. Try finding the connector at the link below:

https://connectorexperts.com/ag-1859...SAAEgKVPfD_BwE