Knock sensor is on the back of the engine block, under the intake manifold and in the middle of the block. It's kind of rare for them to fail but possible. I'd imagine you'll have to get the car in the air and try to reach it either through the wheel well or up from behind though someone who has done that repair can say more. You might be able to get it from the top by taking off the intake duct work and throttle body as well but it'd probably be a real tight fit.

 

I - - think - - it's in the back of the block, and it just threads in like a bolt, but I really don't know.
I couldn't begin to tell you how to test it, but I think you should test it before buying a new one.
And as always, try to get an OEM Toyota part. Don't settle for whatever Autozone wants to sell you, it's probably garbage...

 

Knock-sensor doesn't affect performance, so a bad one won't change how the engine feels. It does affect engine durability and if you get bad gas on a hot day, the ECM will dial back ignition-timing when it detects knock & pinging. Otherwise you may end up with cracked piston rings, melted pistons or even holes in the block!

To test, best to do at ECM connector so you can test wiring in between as well:

Automatic: test resistance between term-13 and ground
Manual: test resistance between term-14 and ground

Should be greater than 1M-ohm (> 1000K ohm). But not fully open or shorted. If fully open or shorted, then it might be wiring. Re-test at sensor itself.

 

Please excuse me for lack of knowledge but what and where's the engine block?

 

http://www.toyotanation.com/forum/1...m/forum/130-7th-generation-1993-1997/384319-4afe-swap-problem-knock-sensor.html

Scroll down and you will see a post by Kiwi-Corolla that shows exactly where the sensor is.

 

Yes they do just screw in. Its difficult but no impossible to remove without major disassembly.

I found a REALLY cheap one online from China, so I installed it. The connector broke off on my original one. The Chinese one died in a few months.

Get one from the junkyard. New ones are high priced.

-SP