Knock sensor replace

First make sure that it is the sensor. All of the info that I could find said that to replace the knock sensor the engine must be removed or lowered.http://www.toyotavantech.com/forum/i...cons/icon8.png

http://www.toyotavantech.com/forum/i...cons/icon3.png I drilled a 2" hole and replaced it about 2 hours. The cover is double thick meta.l Resealing the hole was the hard part. I used fiberglass with the doughnut hole in place.
My first plan was to use a piece of angle alum. underneath the???: I had the glass handy.
Later, I thought that a piece of sheet metal pop riveted would be best.
I'll post the measurement and the socket size. I should have measured it, but didn't think of writing about it till later.I's covered up. Either take off the injector rail or drill a peep hole. a good light helps. http://www.toyotavantech.com/forum/i...ons/icon14.png

I've been planning to do this very thing! I'm anxious to see your photos.

[Added years later as a followup to this discussion]

RELATED *ARCHIVAL* Yahoo Previa Group Discussion and File: Knock Sensor Replacement WITHOUT Dropping the Engine? (From 2011)

DO NOT REPLY EXPECTING AN ANSWER - NOT AN ORIGINAL TOYOTAVANTECH POST.

What follows is a bunch of text extracted from a bunch of separate messages on the group. There are discussions regarding two approaches other than engine removal: dropping the engine slightly or drilling a hole in the floor to get at the knock sensor. At any rate, you'll get the gist and I thought it was useful info that didn't seem to be duplicated on other threads (although I could have missed it) nor this TVT thread.
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John In a message dated 2011.02.26 08:09 -0500, MB wrote: I replaced my knock sensor last night and was surprised how quick & simple it was. I was encoraged by George Kokolakis message from over half a decade ago to do it and was glad I did. I took pics and typed up a step-by-step procedure using a familiar format so anyone that wants to do it can do it easily and quickly. It took me less time to do the acutal work than to format and type the procedure. Forget the resistor (which never worked for me), just replace it (I got a genuine Toyota one for less than $100 delivered from Amazon). FYI part number 89615-12050 has been replaced by 89615-12090.

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Michael,Wow! - what a great write-up -- not just the content (which is great), but the details of the presentation - pictures, layout, choice of font/etc for reading in a garage, and the organization, with tool recommendations. [Operationally, may I ask what editor you used before generating the PDF?] Far better than the FSM. As always, a blessing to this list.

John,I used MS Word, but I had some copy & pasted pages from the All Data info on the Autozone website. I just used their formatting. After several typo corrections I converted to PDF. I did search for 45 minutes to find any engine picture that would show the knock sensor clearly and I only found it on ebay so I hope no one gets tweaked about that. No originality here. I had to list the tool recommendations since I did the job at 0130 am and I didn't have a 27mm deep socket. There was no store open that carries one, so I looked online for the equivalent and I lost an hour driving to the base just to get my 1 1/2socket from my toolbox at work. But, wow! With a new ECT Sensor and new Knock Sensor, no more fail safe mode (timing retardation) and my transmission shifts so much better. It feels all new again!

Marc White wrote: A friend is looking at a Previa and the Check Engine Light revealed a knock sensor code... I have seen these when the engine is out but is there a process for replacing them with the engine intact? In other words, has anyone done a work-around and ct an access panel or some other tricky (cheap) way to address this?

On Jul 11, 2011, at 1:04 PM, ilvcc_98 wrote: see 'knock sensor replacement' in Files section-

How is a bad sensor diagnosed, other than low power? Does the ign advance plot on a scanner show any particular pattern?

On Jul 11, 2011, at 6:05 PM, Steve Jordheim Replacing the sensor doesn't remove the case of the code. Don't blame the sensor for telling you there was a knock condition of magnitude to set a code. Check/Do normal maintenance first. -Steve J

Marc White wrote: Good call but it is not his car (yet). The issue for him was the knock sensor was shot, does it really require over five hours and dropping the engine/trans like he read in a manual... I didn't think it did and that pdf in the files section said 1.5-2 hrs, which gave him alternative info. We'll see if he ends up buying it... Thanks. Marc

I made the pdf file that you are referring to. If your friend follows the instructions,this should not be a problem for him. It wasn't hard at all and that time figure includes setup and clean up.I still marvel over the fact that the the engine doesn't go into constipation mode no matter how hard I push it! I want to race against my 2007 Sienna, but I can't drive both at the same time.

I took some measurements today, but I won't have time until Saturday to do the actual work. But, the knock sensor is on the lip of the block, and in the middle of the intake runners. So, I'm going to unbolt the passenger seat, roll the carpet back, and drill and 2.5 in. hole directly over the sensor. The hole needs to be 4 in. from the edge of the lip when the access panel is removed. I chose a 2.5 in. hole\r because I fond some 2.5 in. rubber piggy bank stoppers on eBay to fill the hole afterwards. What's more, at 2.5 in. I should be able to manipulate the connector with my fingers, and remove the knock sensor with a socket and and extension

The process worked perfectly. If I remember correctly, I measured 7 in. from where the corner bend ends on the back lip of the open access panel, towards the front of the van, and 4 in. in from the lip closest the center of the van. And, the knock sensor was melted; believe it, or not, not crushed, or the wire torn from the head installation. It was probably throwing the code the whole time, but I didn't know it until I replaced the dash light bulbs awhile back. The low fuel light is stuck on now too, so that would make sense. They were on so long they burned out.

Thanks for the excellent write-up! And I appreciate how much more time it took to create it than it did to do the job. I dream of doing many more write-ups than I actually wind up doing.
And it's not too late. I still haven't replaced the one I had in mind when I wrote my other post on this thread. I sold that van to a friend and promised him I'd do it later. It's now years later... He still drives the van and lives close, and I have the new sender, so I put that on my project list for the summer.

The old "Yahoo Group" post was not me doing the work or the write-up; I archived the Group and occasionally transplant what looks to be useful to here. There's often a decent amount of stringing together text from multiple threads to make a summary, but I'm usually not the original contributor(s).

Thank you for posting this, have heard of the timing retardation/ knock sensor problem and resister fix.
Good to know you can replace the sensor without removing the engine.