sinkut,
First - invest in / get a copy of the FSM (Factory Service Manual) - this manual would answer your questions.

The ECU coolant temp sender needs to be checked against a defined range of resistance at a specific temp.
If you want a more accurate test, you pull it off, test it in ice water, at room temp, and in boiling water.

The 02 sensor is best tested while active/hot. It will "dither" or produce a specified range of voltages, back and forth X times per specific unit time...

Again, the FSM has the specifics.

22REturbo.net




1988 4Runner
22RTE core, turbocharged, megasquirted...