Has anyone done the knock sensors on the 4.0L?

Girlfriend’s 4Runner with the 4.0 has thrown the traction control light and check engine light, when I ran the code it was indicating the knock sensor was faulty. My jaw dropped when I saw the 20 hour estimate for doing the sensors by the book, but there was mention of people replacing the sensors and harness without having to take the heads off , by instead cutting the bracket that holds the coolant pipes that are obstructing the sensors from being easily removed. If anyone has done this, seen any videos or threads with this or knows a guy who has I would love all the information possible. Thank you

 

The most likely cause is mice chewing on the wiring. If it is confirmed that is the case, consider turning it in on your comprehensive insurance. If you decide to tackle it yourself, here’s the step by step.

https://www.tacomaworld.com/threads...p0333-diy-knock-sensor-harness-repair.547066/

 

Very hard, I can do them quickly, but I have years of experience and many 12mm wrenches with various angles.

It's almost always the subharness.

 

Never heard of knock sensors needing replacement. I feel like a misfire interpreted by them would result in a misfire code, not a knock sensor code

and that if there was a knock sensor code, depending on what it says, may indicate faulty wiring leading to them

I wonder if a torch helps for that
to heat up a wrench until it glows hot red and then bend it into a certain shape in a vice
a cheap extra wrench maybe

 

Mice got mine 6 days before I needed the truck to tow a trailer on a cross country move. Luckily I have a good mechanic for jobs I can't/won't tackle myself. He managed it in 5 hours, some $800 at the end of the job, using a bit of a hack for access which I believe was what you mentioned with the bracket cut/replacement. Apparently the damn things are down in between the cylinders in the block and the typical access involves pulling the head. Whoever at Toyota thought a goddam sensor replacement having a 20hr book time was ok should be drug out back and shot.

 

I’ve cut, bent, and welded lots of wrenches and sockets over the years. I’ve made box end wrenches with about a 1” offset. I made a 1/2” really deep socket for adjusting E brake cables. About 6” long. Sometimes you just can’t get where you need to be with conventional tools.

 

It's true. A good mechanic has custom tools in his arsenal as well.

 

Then there’s this rocket scientist.

 

Hey I'm one who cut the bracket holding the coolant pipes together to remove. I reinstalled without reconnecting the cut metal tab bracket and its been about 3 years now and no leaks. I was on another thread I'll try to find it, had some good info in it. I replaced both knock sensors and harness since i was so far into it. I used my M12 sawzall with short hacksaw blade and took my time cutting the tab that holds the two pipes together. It's aluminum but doesn't cut as easily as I thought it would.

Here it is:
https://www.tacomaworld.com/threads...p0333-diy-knock-sensor-harness-repair.547066/

 

I think that one flunked. Who TF decided that was a good place for a starter...? Especially with cars that shut off at lights, starters aren't going to last as long with the workout their getting.

What motor is that out of? So I know to steer ppl away from it....

 

That was my first thought too when I heard of the start stop function a handful of years back..

 

I just had both mine replaced. Turns out I had a head gasket leak, and the coolant was building up on the sensor.
My mechanic definitely did the breakdown in about 3-4 hours.



So, two head gaskets, two knock sensors, one air manifold gasket, and a hydraulic tensioner later....
Ramen noodles with a sriracha based sauce, follow me for more recipes.

 

Cadillac did it. I’m not sure if there’s other engines like that.

 

Toyota put the starter in the same spot on the 4.7L V8 and possibly others

 

Forgot to update, but I did the knock sensor replacement with the help of this awesome video https://www.youtube.com/watch?v=pRwMXzAH19w Was fairly straight forward, only thing I recommend is to order replacement O rings for the coolant pipe, the old ones leaked when I put it all back together.

 

Ugh...this doesn’t sound like a fun project.

 

We had an explosion of mice around here a few years ago and quite a few knock sensor wiring issues. Yum, yum that soy wire insulation + warm place to hang out on a cold night.......
But I digress. Yes it can be done without removing the heads. Since I never ever wanted to go back in there again I stuffed that area of the 'V' under the pipe with bronze wool. Mice will not go near it. Not a problem with shorts occurring if you just keep it away a little, besides the connectors are not open.

 

Not knock sensor related but a squirrel decided to chew through my abs harness. Turned that one over to insurance. 500 deductible...cost 5300 to replace, lol.

 

My local shop got further into the diagnostic process than I expected, offered a couple options and ended up just replacing the harness…which I appreciate greatly. I did not want to loose a summer weekend tearing into this project.