Sorry if this has been covered. I haven't been active here since I built my 88 crawler. My daughter's 97 4Runner with 3.4 can't pass emissions and get registered until I fix this.

It has a P0330 knock sensor bank 2 code. I replaced both knock sensors and the harness with OEM Toyota parts. Got it all back together, cleared the code and it comes back.

I tried a hack I saw where you jumper the two sensor wires together but, no change.

Am I going to have to cut open the harness and chase the sensor wires? Any other suggestions? ECM problem?

 

I verified continuity from the new harness through the first connector. I stripped the harness back toward the ECM. The harness has a gray wire to one knock sensor, a black wire to the other sensor and a brown wire that goes back into the harness a little ways and then connects to the shielding on both the sensor wires. Both the gray and black sensor wires at that point each go inside a thick blue wire with a yellow stripe. Looks like it's just a shielded section in the engine bay because it doesn't go to the ECM like that

I don't have a schematic but, I do see a black and a gray wire going to the ECM. If I have continuity from the sensors to the ECM connector does it mean I have an ECM problem?

Is there anything else that can give me the P0330 code?

Anybody?

 

Maybe that motor is "knocking" or maybe something is loose giving the knock sensors enough signal to flag knock, it could be a loose component or something unrelated to the engine or actual engine knock usually due to unmetered air entering the intake/lean condition or ignition/ timing. To pass you could try to remove and isolate the knock sensors and zip tie them and see if it flags it still, but it doesn't tell you what is causing the knock if that solves it but eliminates wiring as an issue although a crude method, not easy to try but might give you a pass until you determine the cause.

 

Hmmm, something else to think about I guess. Would a lean condition give another code? All I have is P0330 knock sensor bank 2. I can't "hear" any unusual noises. I realize the sensor still can. If I got low quality gas and got knock, I could get this code?

I appreciate the response, thanks! I hate dead end threads so I'll post up once I figure this out. My search found a bunch of dead end threads for this exact problem.

 

FIXED IT!

Malcolm99 got me thinking. Maybe it WAS picking up knock. I couldn't hear it but, I put some premium gas in and drove around for a while. Code came back. I sprayed carb clean around areas to check for vacuum leaks. No leaks. If I drove under 2000 RPM no code. Hmmm, maybe it's starving for fuel?

Replaced the fuel filter. FIXED!!! Troubleshooting 101, check the basics first.

The good thing is everything I replaced needed it. The one knock sensor plastic top crumbled off when I tried to unplug the harness. So did the harness. The intake tube and several vacuum hoses and the PCV shattered when I took them off. The rocker boxes were leaking like crazy so I resealed them also. Put new spark plugs in while I was there. Cleaned the MAF sensor.

Thanks for the reply Malcolm99

 

As far as I know ( through my own trials and tribulations) the codes related to the knock sensors only inform you that there is an issue with the ECU getting signals from the sensors. It could only be an issue with the harness or sensors themselves.

 

Your suggesting that the ECU won't put out a code if the vehicle gets real knock?.. You are correct that P0330 is a circuit malfunction, but P0325 is knock detected bank 2 for example and usually pulls timing to protect internals, I wouldn't rule out real knock if I got P0330 or any knock related codes, and its possible that multiple codes pop up or sometimes one is pending, regardless the ECU does flag real knock as well as circuit malfunctions via a code. The OP had real knock from what he described as the fix.

 

P0325 bank 1 sensor and P0330 bank 2 sensor codes have to do with the sensor circuit malfunctioning, not the engine.

I guess I could be wrong, all I have learned was from extensive reading on the form.
​​​​​​​I can say I have never had a knock code after installing supercharger. On California gas, before fuel mods and methanol, especially when traveling the mountain passes I know I had some serious knocking going on...

 

They could be due to either wiring, knock sensor malfunction or actual knock. If you get excessive knock it would flag it as one of those codes, and when you look up the fix in detail it could be any of the mentioned problems include real knock, knock sensor failure or circuit malfunction. Real knock will cause either of those codes to appear if it is excessive, and then you get to determine if its any of the mentioned issues through process of elimination. On my car I have a eprom ECU so you can see real knock as it happens and the car pulls timing, to much knock and the Code pops up and check engine light stays on and pulls timing across all RPMS, adding meth at 10psi to 28psi works for my 4G63T aswell and I doubled the injector size so my injector duty cycle was around 75% leaving lots of room for temperature fluctuations. The 5VZ-fe is not commonly effected by knock unless unmetered air is entering the system causing knock.

 

 

OK here's an update. I also had doubts the fuel filter fixed it. It looked original like everything else on this truck so it got changed anyway. New sensors, new harness and I checked the wires clear back to the ECM. The code came back almost a week later and I was out of ideas so I took it in for diagnostics.
It was the new sensors. Pretty sure I bought counterfeit junk. The packaging looks legit and so do the sensors. Price too good to be true. eBay and Amazon both sell from a lot of different vendors from super cheap to pretty expensive. I went with the realistic priced ones and the feedback was all good on many sold. Still got burned.

The dealer price on the 89615-12090 Sensor,Knock is over $200 each. Toyota parts deal is close to that plus tax and shipping. I still took a chance and bought two off Amazon but, the seller was a Toyota dealer or parts source. They were $139 each. I took another chance and bought one of them as used/open box. Guaranteed as new, just no box from the same seller for I think $62.

The first sensors had the Matsu˟˟˟˟a "M" on them. I'm assuming that's what it was. The second new set I got has Denso on the plastic top and the bottom threaded part has a hole. The others were solid. I should have taken pics. The Denso ones also had a black sealer around the edge of the plastic where it attaches to the metal body. The bad ones center plastic section were actually loose in the metal body. I could spin them. I'm waiting for a refund from the seller. They requested pics and I sent them the diagnostic report proving they were bad.

Its easy to say I should have bought parts from the dealer. I actually agree, I used to work at a dealership. However, my daughter just moved to another city to start a new job and can not afford it. My labor is free and I found the best deals on parts I could. Sometimes you get bad parts. Even from a dealership.

That said, I just wanted to complete this thread with accurate information. Hopefully this helps others. Dead end threads suck. There are a bunch out there on this exact topic. Thanks to those of you that replied. I appreciate it.