1MZ-FE engine knock sensor codes will not go away

Can you clarify what you are getting when you are testing for a short to ground on the shielded wire? You should not have continuity to ground. Basically the body of the sensor grounds the circuit through the engine block.

Here is the test that we need to run on the sensor itself. Let's double check this and then we need to zero in on the wiring if you have continuity to ground on the shielded wire.

I think we need to step back. The shielded wires are there to protect the wiring so it doesn't pick up any other RF signals because the PCM needs as clean a signal as possible. So the shielding is not there for ground. If you look at your diagram I circled the ground locations. This is after the sensor. So the shielding portion where I put pointers, is the shielded part because this is the signal wires to the PCM.

I attached the diag for these codes. Basically it is telling you that the PCM is not getting a signal from either sensor. So that means there is either an issue with the sensor or the wiring. The fact that you have 30 ohms of resistance on these wires is what we need to address.

What I would suggest is trying to run new wires from the sensor to the PCM. Don't worry about using shielded wiring at this point. You just want to prove out that it is wiring.

When you connected those wires, did you cut the other ones so that you were only running on the new wires or did you just overlay them?

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It is possible. Basically hertz readings are measurements we use for measuring AC signals or bandwidths of digital signals. We also use it for measuring vibrations and the knock sensor is used to measure vibrations in the engine that the PCM will interpreter as engine knocking so it can adjust fuel to try to get rid of the knocking. If you are running the engine at 4000 RPM and you are getting 4300 hertz, I would expect to see that. I have never done this so I could be wrong but just from what I am seeing, I don't think that is an issue.

As for the sensors, that is a hard call and I am not sure I would do it. Clearly the Toyota sensor is of better quality but I doubt these other sensors would trip this code out of the box like this. At least not multiples of them. Maybe I would get one of them and if the code goes away on that side I would get the other.

Rock and a hard place. I will tell you what, I will ask the other guys to review this post and see if I am missing something. I read through it again but it is late so maybe I am making an assumption that is wrong.

When I worked in engineering I worked with motors among other things we had a few engine returned to us that were down on power what it turned out to be was metal shields around the knock sensors the bolts holding the shields were not tightened at the factory so the shields were loose and rattled setting off the knock sensors. Check for anything like that aloose bracket, shield etc. You have no idea what this man has done prior to even checking for the codes. As true as things are you as a mechanic know that people don't always give you the complete story.