I replaced my knock sensors recently. Check engine light came off for a week but then returned. OBD says harness wires to knock sensor may need to be replaced. Could I get by without replacing harness inasmuch as I’ve replaced the knock sensors? Or am I stuck having to replace harness?
WOW, so much for Toyota alleged quality, 2023 required knock sensor replacement…
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I suspect that you have an open circuit fault. If you want the check engine light off and the engine to operate properly, the wiring problem will need to be repaired. Because of the amount of labor involved, I usually replaced the knock sensor harness or connectors when replacing knock sensors.
This vehicle is ten years old, 2023 is the default in the scroll down when a model year is not selected.
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If this is really a 2023, you should not replace anything. just bring it to the dealer under the warranty.
The knock sensor signal is how the drivetrain computer determines if the engine timing is too far advanced. If it is too far advanced, that will damage the engine parts; so if the knock sensor signal isn’t reaching the computer, and the computer has determined it’s b/c the wire between sensor and computer isn’t connected, computer has no choice but to set ignition timing retarded enough engine won’t be damaged. But that will significantly reduce your available engine power. That’s why for the engine to work properly, the knock sensor needs to reach the computer.
This is sort of like attending a rock concert, and discovering you can’t hear the music. Is it b/c the musicians’ instruments are faulty? Or b/c they are only pretending to play? They are playing, but their guitar’s aren’t connected to the sound amplifier input? Signal is reaching sound amplifier input, but sound amplifier isn’t powered up? Speaker’s disconnected? Well you get the idea, lots of possibilities. By analogy you attempted to solve the problem by replacing the instruments, and discovered you still can’t hear the sound. So now you have to test each of those other possibilities one by one. Either that or just replace all the other stuff, which would be sort of equivalent to replacing the car’s wiring harness component for the knock sensors.
Just curious , how did you find the vehicle age ?
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Knock sensor problems generally occur after ten years, I’m not fooled by the title.
And that’s why you get paid the big bucks. 
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Nevada is keeping all of us honest … lol …