Knock Sensor headache

[Atreyus]

So here's the story, two years ago I had the Knock Sensor P0330 code bank 2 circuit 2. I took it in to my dads mechanic he has known for over 40 years to get it fixed. They said they got it fixed but code was not showing on the dash but still in the computer. It drove fine for the almost 2 years I've have driven it until now. Fast forward to now, I get it smogged and it fails because of the Check Engine light. Same code still in the system. The guy at the smog place tells me that they probably spliced the check engine light to another light. Take it to a shop down the road and they find they had went into the dash down the wiring harness and spliced it to my oil light so that when I start the car it goes off. So not only did they screw me on the repair but also having to pay to get the check engine light operating properly. So I take it to my friend to get the code serviced. He has replaced both knock sensors and wiring harness, along with the manifold gaskets. My question is why is the code still showing in the computer? Could they have tampered with the ECU? Or is there a short somewhere? I'm like losing a lot of money trying to get this fixed, My registration is due in September and If I don't fix this issue I might just end up selling it. It sucks because I'd done a major maintenance overhaul on my truck and this happens. Any help would be greatly appreciated!

 

[BlackCat914]

Has anybody phsyically cleared the code with a scan tool? A code will show in history for quite some time before it's automatically cleared out.

 

[Atreyus]

yeah the code has been cleared but came back showing knock sensor.

 

[Stick Figure]

you could have really bad actual knock, a bad sensor, bad ecu, or ........

I haven't heard of the specific problem on the 4Runner, but the MA70 Supra's had an issue with throwing knock codes because of the aging wiring. rewire has to be done with shielded wiring, if unshielded was used they can pick up interference, and cause the CEL. try doing some google searching for knock sensor rewire for more info.

 

[Atreyus]

Well the wiring harness that connects the two knock sensors and the two knock sensors themselves are new, my friend is going to trouble shoot the wires going into the ECM and the ECM itself today hopefully they find it soon because I need to get smogged and my registration is up September.

 

[rebelbowtie]

where are the k-sensors on the 3.4? I know on my Chevy's theyre under the intake in the lifter valley and they are prone to getting debris and water pooling around the sensor and causes them to go bad. I had to replace my sensors 3 times over the course of a year before i siliconed the rubber boot that went around the sensor. that finally fixed it for me.

 

[Atreyus]

same on my 4runner if it doesn't get fixed before September I'm going to end up selling it, what sucks is that I did a complete maintenance overhaul on it might end up getting a new tacoma lol.

 

[Atreyus]

were checking the wires that go to the ECU and the computer itself hopefully we find out what's wrong. If anyone has suggestions please chime in!

 

[Atreyus]

So I changed out the ECM with a new one and I'm still getting the codes, what could be the problem?? I'm losing it lol and if I don't get this fixed I'm just gonna trade it in for a new tacoma ugh!

 

[SandManJTS]

KSs have been replaced twice now.

I bought this '96 4Runner knowing it had a knock sensor issue. Owner said the knock sensor(s) had recently been replaced and I thought to myself, no biggie.

Per various posts on 4Runner problems, I thought I'd tackle this myself. Bought 2 new sensors on the internet because they were $100 cheaper each than local parts store and $250 cheaper than the dealer and bought a new factory harness on eBay. Took all day to pull the manifold stuff and put it back together. Drove it 3/4 mile and the cel came back on.

Then I used the old harness and 2 old sensors and mounted them on the outside of the engine for test purposes and drove another 3/4 of a mile and the cel came back on.

I visited with a gal at the local parts place and she said that I need to look at the label on the alternator to see what brand it was. She said if it's a Nippondenso, I need to install (Nippon)Denso knock sensors. This kind of, and still kind of not makes sense to me.

Before I spend another $300 and another day replacing the ones I just installed, can someone shed some light on this?

'96 nice original "Feed Store Find"

 

[Rock_Rat]

So I changed out the ECM with a new one and I'm still getting the codes, what could be the problem?? I'm losing it lol and if I don't get this fixed I'm just gonna trade it in for a new tacoma ugh!

Read my thread http://www.toyota-4runner.org/3rd-gen-t4rs/184979-knock-sensor-0330-everything-replaced-puzzled.html You MUST use OEM sensors on these rigs. The system is simple

• ECM
• Wiring Harness
• Sub Assembly
• Two Sensors

Sensors don't "control" they "sense" and send piezoelectric signals in the way of voltage to the ECM to advance or retard timing. The ECM monitors the sensors for voltage (an electrical charge from crystals inside the sensor) and processes the information it sends. If it doesn't see voltage then you'll get one of the codes depending on which bank has failed. The ECM will have to use a default value. That's why your 4runner goes into "limp" mode.

Only one code - 0330 tells me the ECM and the wiring harness are working correctly. In troubleshooting this is called "half-splitting" or narrowing down your "path of influence" to your "critical path". Now you're down to just two components - sub harness assembly and one knock sensor. Either of those are driving the code and the CEL. With the intake manifold off, I would highly recommend you replace both sensors with OEM and spend the extra $25 for the sub-harness. Ensure it's not pinched when you install the manifold back on. Don't waste your time splicing the grey wire into the black like I did.

Spring for new manifold gaskets only because once you "crush" a gasket it's more susceptible to vacuum leaks. Tape and cover ALL holes and valleys. The last thing we want to see on here is a thread on how to get a washer or something out of...

Keep in mind the ECM has what is called NVM or non-volatile memory. Basically it will keep the code stored in it's memory until it runs through it's reset procedures. Once clear, you can run it through DEQ.

Please keep us posted. Hate to see you going through the pain and angst on something so seemingly simple.

 

[4Runner-Dan]

Read my thread http://www.toyota-4runner.org/3rd-gen-t4rs/184979-knock-sensor-0330-everything-replaced-puzzled.html You MUST use OEM sensors on these rigs. The system is simple

• ECM
• Wiring Harness
• Sub Assembly
• Two Sensors

Sensors don't "control" they "sense" and send piezoelectric signals in the way of voltage to the ECM to advance or retard timing. The ECM monitors the sensors for voltage (an electrical charge from crystals inside the sensor) and processes the information it sends. If it doesn't see voltage then you'll get one of the codes depending on which bank has failed. The ECM will have to use a default value. That's why your 4runner goes into "limp" mode.

Only one code - 0330 tells me the ECM and the wiring harness are working correctly. In troubleshooting this is called "half-splitting" or narrowing down your "path of influence" to your "critical path". Now you're down to just two components - sub harness assembly and one knock sensor. Either of those are driving the code and the CEL. With the intake manifold off, I would highly recommend you replace both sensors with OEM and spend the extra $25 for the sub-harness. Ensure it's not pinched when you install the manifold back on. Don't waste your time splicing the grey wire into the black like I did.

Spring for new manifold gaskets only because once you "crush" a gasket it's more susceptible to vacuum leaks. Tape and cover ALL holes and valleys. The last thing we want to see on here is a thread on how to get a washer or something out of...

Keep in mind the ECM has what is called NVM or non-volatile memory. Basically it will keep the code stored in it's memory until it runs through it's reset procedures. Once clear, you can run it through DEQ.

Please keep us posted. Hate to see you going through the pain and angst on something so seemingly simple.

^^^^This guy speaks the truth. I just went through this, too. OEM. OEM. OEM.

Buy from this place on eBay. Much cheaper than dealer and they are OEM.
Toyota Lexus 8961512090 Ignition Knock Detonation Sensor 89615 12090 | eBay

 

[Oneluv13T4R]

he is exactly right..this goes the same for O2 sensors and all toyota sensors for that matter, we all figure this out the way you are now. One thing you cant go aftermarket with is sensors, unfortunately.

 

[papichyno]

^^^^This guy speaks the truth. I just went through this, too. OEM. OEM. OEM.

Buy from this place on eBay. Much cheaper than dealer and they are OEM.
Toyota Lexus 8961512090 Ignition Knock Detonation Sensor 89615 12090 | eBay

Anyone have a diagram showing where the knock sensor is on a 96 4runner?

 

[JayRolla]

I've had same issues on dsm's not using Oem. Even the denso part stores did the same thing. Must me Toyota branded Oem.

 

[habanero]

Anyone have a diagram showing where the knock sensor is on a 96 4runner?

96 3.4...
Under the upper and lower plenums...

Under the lower intake manifold...

Lower intake manifold moved aside, you can see them....

Here...

 

[Lira3689]

Read my thread http://www.toyota-4runner.org/3rd-gen-t4rs/184979-knock-sensor-0330-everything-replaced-puzzled.html You MUST use OEM sensors on these rigs. The system is simple

• ECM
• Wiring Harness
• Sub Assembly
• Two Sensors

Sensors don't "control" they "sense" and send piezoelectric signals in the way of voltage to the ECM to advance or retard timing. The ECM monitors the sensors for voltage (an electrical charge from crystals inside the sensor) and processes the information it sends. If it doesn't see voltage then you'll get one of the codes depending on which bank has failed. The ECM will have to use a default value. That's why your 4runner goes into "limp" mode.

Only one code - 0330 tells me the ECM and the wiring harness are working correctly. In troubleshooting this is called "half-splitting" or narrowing down your "path of influence" to your "critical path". Now you're down to just two components - sub harness assembly and one knock sensor. Either of those are driving the code and the CEL. With the intake manifold off, I would highly recommend you replace both sensors with OEM and spend the extra $25 for the sub-harness. Ensure it's not pinched when you install the manifold back on. Don't waste your time splicing the grey wire into the black like I did.

Spring for new manifold gaskets only because once you "crush" a gasket it's more susceptible to vacuum leaks. Tape and cover ALL holes and valleys. The last thing we want to see on here is a thread on how to get a washer or something out of...

Keep in mind the ECM has what is called NVM or non-volatile memory. Basically it will keep the code stored in it's memory until it runs through it's reset procedures. Once clear, you can run it through DEQ.

Please keep us posted. Hate to see you going through the pain and angst on something so seemingly simple.

Thanks that is great info, I had recently change my knock sensor with matsuchita, like 8 bucks less than OEM and new harness. I have put everything back together and I let it sit for 30 minutes running, before I erased the codes. I notice that there was a lag on acceleration and not just one bank came back both sensors where not registering, and to make everything worse I started to notice a slight knock in my engine. is this part of saving 16 bucks, why the knock sensors dint work or it's part of bigger problem?, if so can some one explain or give me advice what is the next step, I just received my replacement from Rock Auto but this time I got the Denzo OEM.

Sent from my 2PQ93 using Tapatalk

 

[Tinigunner11]

Thanks that is great info, I had recently change my knock sensor with matsuchita, like 8 bucks less than OEM and new harness. I have put everything back together and I let it sit for 30 minutes running, before I erased the codes. I notice that there was a lag on acceleration and not just one bank came back both sensors where not registering, and to make everything worse I started to notice a slight knock in my engine. is this part of saving 16 bucks, why the knock sensors dint work or it's part of bigger problem?, if so can some one explain or give me advice what is the next step, I just received my replacement from Rock Auto but this time I got the Denzo OEM.

Sent from my 2PQ93 using Tapatalk

How much did you pay for sensors? There is an eBay seller who sells oem ones for $45 right now. Here's s link to my thread: http://www.toyota-4runner.org/3rd-gen-t4rs/233730-good-deal-knock-sensors.html#post2620382

 

[AlecT]

Knock sensor code from bad timing?

So, here’s my story. As short and simplified as possible. Last year I had my timing belt and water pump replaced by a shop. Shortly after getting my car back, CEL came on showing the knock sensor codes (sensor 1 and 2). I replaced both knock sensors and the wiring harness with OEM parts. CEL still came back on. Ohm’d the wires, everything came back good. Replaced ECM with a junk yard 4runner of the same year, numbers on the ECMs matched up, etc, and I had it reprogrammed. Still the CEL.

Now here’s my main point to the thread:

1) I read that the knock sensors MUST be torqued. I of course, did not torque them. However, I was very careful not to over tighten. So I can say with 90% confidence that they were not over tightened.

2) A mechanic I know suggested that the the timing could be off slightly (by a tooth or so) causing it to through the knock sensor code.

I’m hoping someone can shed some light on the subjec by debunking either of these theories or explainin why one theory makes sense.
Thanks!

 

[Rock_Rat]

So, here’s my story. As short and simplified as possible. Last year I had my timing belt and water pump replaced by a shop. Shortly after getting my car back, CEL came on showing the knock sensor codes (sensor 1 and 2). I replaced both knock sensors and the wiring harness with OEM parts. CEL still came back on. Ohm’d the wires, everything came back good. Replaced ECM with a junk yard 4runner of the same year, numbers on the ECMs matched up, etc, and I had it reprogrammed. Still the CEL.

Now here’s my main point to the thread:

1) I read that the knock sensors MUST be torqued. I of course, did not torque them. However, I was very careful not to over tighten. So I can say with 90% confidence that they were not over tightened.

2) A mechanic I know suggested that the the timing could be off slightly (by a tooth or so) causing it to through the knock sensor code.

I’m hoping someone can shed some light on the subjec by debunking either of these theories or explainin why one theory makes sense.
Thanks!

#1) Not your problem - Not correctly torquing knock sensors will NOT throw both codes.

#2) Not your problem - The code is an indication problem not a timing problem. The ECM is not seeing the sensors, thereby throwing the fault codes.

Since it's BOTH sensors then you have a COMMON problem effecting them both.
Possible problems:

• Both "OEM" sensors were not from a reputable source and they look OEM. (You didn't mention where you purchased them)
• The sub-harness is bad. There's three wires in there, black, grey, and orange (I think).
• Did you do a continuity check on the wires? All should read 0.00.
• Is it connected correctly? That was a recent solution on here about a month ago. Check your connector. It might not be snapped in correctly.
• Is it pinched under the manifold. There's a small valley designed for the harness
• Check the harness going from the sub-harness to the ECM for damage going.

This is a start.
Report back. I'm more interested in where you bought your sensors than anything else.