The "knock sensors" for the Avalon 3.0 are facing the firewall on the engine block just below the cylinder head ,their are two knock sensors .
They are located down in the engine block valley. Accessing the knock sensors requires cylinder head removal..........sorry.
replace it.
Knock sensor is attached to the engine side facing the firewall. It's not easy to reach.
It can be a sticky caliper or you need to change brake pads.
It should be in the side of the engine facing the firewall.
The knock sensor are located in the valley between the cylinder heads on V6 and V8 engines V8s have two knock sensors
On 4 cylinder you can find it on the side of the engine facing the firewall.
Knock sensor is located in the wall of the engine block facing the firewall. You have lift the car if you want to reach it.
It's screwed in the side of the engine facing the firewall.
It should be on the back side engine. The side which is facing the firewall.
Sienna's have two knock sensors located in the valley underneath the intake manifold. Replacement is a three hour job.