booter24

Hey guys I just had my truck in for a coolant leak that was leaking into the intake. Fixed the leak, new cap and plugs, and radiator flushed. When I took the truck in I had no check engine light on but when I got it back it came on. It's saying it's a Knock Sensor. When I first start up and start driving it drives fine but after about a quarter mile or so the check engine light comes on and there is NO POWER (you can feel the truck lose power as soon as the light comes on). It takes me FOREVER to get to 55 mph, I literally have to floor it and wait and wait for it to finally get there (it's a 5 speed 4x4) couldn't even get 70 on the expressway the other day.

I'm curious as to if this would be related to the coolant leak and or cap and plugs replacement? Also is this a hard sensor to replace? I'm hoping if I replace the sensor and pigtail my truck will be back to normal. THanks again for any info

MudHippy

Which code is it, 52 or 53?

EDIT: It's probably just a bad connection where the knock sensor pigtail plugs into engine wiring harness. Since it was likely being moved around a lot during the repairs(may have even been, or still is, disconnected). Try making sure it's plugged in tight, or if it is, try cleaning the terminals on those connectors.

booter24

it was code 52. I gotta think something was touched when he was doing the intake issue. Any recommendations on where to get one for a good price?

MudHippy

52 makes sense. That's usually caused by the pigtail connections(either end). It's most likely not the sensor itself needing replaced if that's what you mean by get one. And if you were to replace the pigtail it's going to have to come from Toyota for around $10-$15. The knock sensor isn't cheap. You can get an OEM KS for around $175. Or you can get a cheaper after-market brand for around $115 or so(RockAuto.com)
https://www.1sttoyotaparts.com/oempartscat.html

MudHippy

BTW, I HIGHLY RECOMMEND that you try doing what I suggested before going and buying/replacing parts.

Why?

Because you just paid for a bunch of parts and labor to fix a coolant leak into your intake.

Why does that matter?

Well, the leak was probably at the lower intake manifold gasket(s). And you'll need to remove the upper and lower intakes to remove the pigtail and/or the knock sensor. That means the upper intake and lower intake gaskets will need replaced again too. Which basically means your money thrown in the trash replacing the brand new gaskets you just paid for. If it's just a matter of cleaning up the terminals that would fix the issue. Which it very well could. Did on my 88 3VZ-E, which still has the OEM pigtail and knock sensor it came with from the factory 24 years ago.

booter24

Thanks MudHippy, good info

I'll give it a shot and see what turns out, fingers crossed!!

booter24

Is it possible to clean the terminals without pulling everything out? Also, where does the wiring plug in?

jammin962

The upper plug is underneath the plenum between drivers side fuel injectors. You will have to remove the plenum (upper intake) to get to that plug. The sensor itself, and the other side of the plug is underneath the intake manifold ... to get to that you have to have the whole intake off. .... unless mudhippy knows a trick???

Here's the link to my little thread, I have my 3.oh tore down right now and the pics I have on there show the knock sensor in the middle of the nasty yellow gunk

https://www.yotatech.com/forums/f116...ak-249438-new/

good luck

jammin962

^^^^ Mr. MudHippy could be very right and he makes a good point in a later post ...that ya may as well try the easy (and most likely) connection first before spending all that money again to go down to the knock sensor ... and it is a bit of a PITA too.

MudHippy

You can get to the wiring harness end of the pigtail w/o pulling the plenum(since it's not really underneath it). It's underneath the throttle body, more or less. It's not that hard to plug/unplug the connectors right there(if your hands are small enough). You'll probably need to remove the air intake hose first though, to make it a little easier.

Here's some pics of what it looks like unplugged with the throttle body and plenum still on(notice the air intake hose is removed, and that hose clamp temporarily dislocated).



Is it possible to clean the terminals like that?

Should be. One way or another. But it's giving me a crink in my neck just thinking about it...

booter24

Good Deal......thanks again guys. I'm gonna give it a try and see what happens. Hope my hands are small enough cause if there not then the little wife might be getting her hands dirty!

MudHippy

Yeah, I don't know what to suggest as far as tools or techniques for cleaning those suckers. I used a dental pick on mine to clean them up a bit. Just tried to scrape off/out as much of the corrosion and dirt as I could. Worked for me.

But it wasn't the connection at the wiring harness end that actually needed cleaned on mine when code 52 popped up(they were still pretty clean as they were, and "cleaning" them more didn't solve the code 52 issue). So I did end up having to tear my intake back off, after just putting in back on with all new seals/gaskets. I hadn't even unplugged the pigtail from the KS. But apparently I'd moved the wire around enough to cause a bad connection between the heavily corroded terminals on both the sensor and the connector on that end of the pigtail.

jammin962

Thanks for correcting me mudhippy, good to know. That could save a lot of work for sure!

I am definitely gonna have to replace my pigtail since I'm down that low right now.

Good luck on yours booter24, just be sure when you're cleanin that plug you don't stretch out the female sides of the terminals or you'll never get a good fit again. A thought just popped into my head that maybe the match striking surface from a box of matches could be trimmed and inserted into the female terminals to clean off any corrosion. ..?

booter24

well my mechanic has given everything a shot and it sounds like we are going to have to pull it all out and replace the whole thing. It seems that the knock sensor and pigtail is easy to get but George (mechanic) was saying something about a wire that runs from the sensor up to the wiring by the top intake? I am not mechanically savy at all and have no idea what this is, Wiring Harness?? Whatever it is he hasn't been able to find one.....guess he has even called a couple yota dealers and they said their hard to find. any idea what part he is talking about?

MudHippy

My question is does he know what part he's talking about? And/or what you/we mean by the knock sensor "pigtail"?

In reality they are the same thing, the knock sensor wire is the knock sensor "pigtail". Doesn't really matter what you want to call it. That's the wire that runs from the sensor to the engine wiring harness near the top of the intake. There's only one of them, and that's it. And all you need to know to find one on your own is found in post #4(namely the part # and the link to the OEM parts supplier that the price quote for it came from).

This is it.


Goes here.


If he means replacing the KNK signal wire in the engine wiring harness to the ECU, that's not going to happen. Not without replacing the entire engine wiring harness as a unit. And they're not available anywhere new that I know of. So it would have to be a used one. Part number is 82121-89177 if you want to try looking for it yourself.

booter24

Mudhippy, I sent this link to my mechanic so he could see the pictures and we could get on the same page. He said the part he needs is that green looking plug in the last picture. Is that the part thats hard to get?