Request Knock Sensor Failure advice

RS Dude

RS Dude

Member
History: For several years now I have had a small, slow coolant loss that has increased steadily. Carefully checked all cooling system components but have never seen any evidence of coolant leakage. Also, have for some time now experienced eng pinging on hot days when going uphill, especially when A/C is running. Just last week had a brief but scary, HORRENDOUS knock that sounded like the engine just threw a rod. Soon after I got the Check Engine light on dash and it turns out to be P0330 or Knock Sensor 2 failure.

Question: I suspect that my mysterious coolant leak may be the cause of the knock sensor failure. Anyone who has replaced knock sensor(s) have any coolant leakage from the intake manifold gaskets? Will sensor #1 soon wear out? Was the sub-harness to the sensors faulty or corroded?

Will replace both sensors, wiring harness, and intake gaskets, but at $155.00 per sensor, am reluctant to replace good sensor #1 with and new one.

Any advice is welcome, thanks in advance.
 
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During my replacement of both knock sensors as well as the harness last spring. I found that coolant had leaked in to the valley of the engine. It had pooled up enough to partially submerge both sensors. Whether or not it was the exact cause of the cel for both sensors or just plain old age of both the sensors and harness (300,000 miles) I do not know. However my common sense would tell me anything sitting in coolant that was not designed to would shorten its life. Replace both sensors and harness. I got oem sensors of Amazon for $99 each, search by part number. I got oem harness off amazon around ~$30. It not that bad of a job to replace but enough effort to only want to do once. All that being said if your engine is knocking then you have other issues. The knock sensors only "listen" and report what they hear to the ecu, and only "fail" when the ecu receives a bad or no signal. Replacing sensors and harness will not fix the knock. That is another can of worms. Hope this helps.
 
^^^^ Pretty much spot on.

The wires get brittle and break (heat) or chewed up by rodents taking refuge in there. <<<<----- ONLY USE OEM------>>>> Change both and the sub-harness assembly. Replace your manifold gaskets. Do a search for Rock_Rat "Knock Sensors" and I'm sure you'll find a number of threads on here.

[MENTION=139950]Brenn[/MENTION] is spot on with indication only. K Sensors don't control anything. You need to look into your knock problem. Even when one or both of the sensors fail, the ECU defaults to a safe timing to protect your engine. A failed KS won't cause your engine to knock.

Not a bad post from [MENTION=139950]Brenn[/MENTION] considering it was your number 1 post.
 
Rock_Rat said:
^^^^ Pretty much spot on.

The wires get brittle and break (heat) or chewed up by rodents taking refuge in there. <<<<----- ONLY USE OEM------>>>> Change both and the sub-harness assembly. Replace your manifold gaskets. Do a search for Rock_Rat "Knock Sensors" and I'm sure you'll find a number of threads on here.

[MENTION=139950]Brenn[/MENTION] is spot on with indication only. K Sensors don't control anything. You need to look into your knock problem. Even when one or both of the sensors fail, the ECU defaults to a safe timing to protect your engine. A failed KS won't cause your engine to knock.

Not a bad post from [MENTION=139950]Brenn[/MENTION] considering it was your number 1 post.
Click to expand...

The pinging I described as 'normal' goes away when using premium gasoline, so I consider it normal and occuring in most vehicles I have ever owned.
 
I was referring to this statement in your post about your knock: "HORRENDOUS knock that sounded like the engine just threw a rod. Soon after I got the Check Engine light..." that doesn't sound good at all. Curious to know what it was.

I try to use Techron 99% of the time. Whenever I change to a "no-name brand" I may get a some pinging for a very short period of time.
 
You definitely have something else going on with the noise you described. There is a coolant pipe that runs along the valley of the engine. You may have a leak there. You won't know until you get in there though. Definitely replace both knock sensors if you go in there. I just had this job done a few weeks ago on my 4Runner. The good news is, you can buy OEM sensors for $85 for the pair. Definitely replace the sub wiring harness, as that is what my problem was. That can be had for $24, and it too is OEM. I went with Rockauto for a set of Felpro gaskets for $82 shipped. My local shop charged me $425 total for the labor, and he replaced a lot of the rubber lines around the back of the engine and my supercharger that had started dry rotting. I have already put about 1500 miles on it, without a single issue.

Harness:
Genuine Toyota 4Runner Tacoma Tundra 3 4L Knock Sensor Wire Harness 82219 34010 | eBay

Sensors:
Genuine OEM New 89615 12040 Set of 2 Denso Toyota Lexus Knock Sensor | eBay

Gaskets:
https://www.rockauto.com/en/partsearch/?partnum=MS95898
 
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