The sensor in the front behind the timing cover is one that sends the signal to the ECM. The one on the back of the engine is the for the gauge cluster.
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1997 SR5 4x4 Auto, 99' tall coils up front, OME 906's, Truetrac LSD, Airaid MIT
1999 SR5 4x4 Auto for parts
2011 Camry SE V6
2011 Highlander Limited
back right of the engine up against the firewall. Most likely will need to remove the Heater core hoses for easier access I changed mine it was "that" hard. I took off my hood also, Either a 10 or 12 mm deep socket fit over the sensor and out she came.