1997 2RZ: Coolant Temp....how many sensors/senders?

We've been struggling with a hot start problem that is throwing an ECT code. We have replaced the front Temp Sensor, which may not be the only one. We believe that this one only communicates with the gauge and not the ECU (so it wouldn't solve our problem)

Is there a sensor/sender at the back of the block that communicates with the ECU...some videos reference is, but seeking confirmation here....and anyone got a part number.

thanks in advance. and apologies for the massive image.

 

Yes there are two temp sensors, front and rear.

I'm diagnosing a temp problem off the front sender/gauge right now (it looks like the one you have pictured). The front sender only services the gauge. The rear, on the head at the firewall, is what the ECM reads. Your scanner will tell you if the rear sensor is reading accurately AKA if your scanner is plugged in, the coolant temp is warm and you're getting a temp reading that isn't ~185, that's an issue.

Was trying to get a part number but struggle bussing this morning. Standby

 

Front is 83420-20040 or alternative part number 83420-AA010

Rear is sensor is

$29 89422-35010 Water Temperature Sensor

89422-35010

 

Awesome...Thank you....We've been chasing our tail because it's apparently not widely advertised that there are two temp sensors...hope swapping this one out solves our problems