Toyota knock sensor

 

sam washburn

1 year ago

Good news. I had a long talk with a friend who is a Mercedes trained automotive tech about knock sensors. 1. The ecm does NOT use the knock sensor for anything except when it detects a preignition. 2. If you have a well maintained engine and use the correct octane fuel, it will not knock. 3. If motor has two knock sensors, the second one is just for redundancy. If one dies or is bypassed, the working one will detect all the knocks and the ecm will retard timing to prevent the knocking. So the bottom line is that bypassing a failed knock sensor does not risk damaging your engine.

https://www.toyotanation.com/threads/fooling-the-ecm-sharing-1-good-knock-sensor-for-2-ecm-inputs.85721/page-2

  bypass by doing the Rev thing? Or by wiring it to only use the 1 knock sensor that isn't throwing a code?

But I'll wire them both to bank 1 today (my good one) since it's throwing code for bank 2!

I guess I will use premium fuel for this time just to be sure.

I did your mod and have been driving for approximately 300 miles now check engine light went out by itself and I just wanted to say thank you.. save me some money did not want to go through the process of taking the intake off and replacing all that mess..

They are labeled as bank 1 and bank 2, but they are more so redundancy in pairs.

Yup, it should work. It worked for my 1MZ-FE engine which I used one knock sensor for both sensor wires.

To reach the ECM you have to remove the glove box and a plastic panel underneath.

With the glove box out of the way, the ECM connectors are readily accessable, infact I didn't even have to unbolt the ECM. Simply, gently unplug the 16 pin connect and fish it downward where you may find more room to splice the wires you need.

I did this exact thing a few days ago and it worked like a charm!
No more CEL and my timing is back to normal. Now I just gotta hope that the other knock sensor never goes out... lol.

 I am thinking of bolting it to the block and connecting to the old connector. It may not have the exact resistance to knocking, but should give some active use. Since the connectors come out under the intake manifold, can we jump them there to share if we cannot use the other sensor?

So I cut the wire for knock sensor 2 (remove glove box, 4 Phillips screws and 1 bolt on 2001 Camry LE, V6, 2 knock sensor inputs are on R11).

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relocate 1 knock sensor and split it to both inputs on the ECU. Apparently it's a common issue for the wiring going to the knock sensors to go bad, and the effort to get to them is not worth it for some people. https://www.youtube.com/watch?v=AehVCIebHas

https://www.youtube.com/watch?v=UYKHOONXD5s

99 Toyota Avalon 3.0L ***KNOCK SENSOR & SUBHARNESS*** PT 2

https://youtu.be/VSjItDvVOzE?t=495  

2000 - 2004 Toyota Avalon knock sensor location / replacement

relocating knock sensor:  https://youtu.be/6WZ5WEdFtc8?t=621

why bypass a bad knock sensor:  https://youtu.be/mp3i3StILws?t=273

UtahSleeper

8 months ago

I replaced 1 sensor, but the sensor is sending to the ecu for both sensors. That's what the wire modifying was for.

https://www.toyotanation.com/threads/01-p0325-p0330-knock-sensor-codes-replaced-everything.1495562/page-2

Lack of a good ground connection at the ECU might explain some of these knock sensor problems that aren’t fixed by replacing sensors and the sub-harness.

3+4 are shielded ground.  1+2 come from knock sensors.

disconnect EB1 and test for continuity between 2&4 and 1&3 on both sides of the plug. Is there continuity of either plug at these 2 points? If so, the wire is shorted to ground, and that is the problem.

As far as finding the EB-1 connector its fairly hidden.. Easiest way for me anyway was to stick my left hand in around the cruise cable to the left of the air cleaner hoses and go underneeth the evap line with the green cap on it. If you imagine where the center of the V would be in relation to the engine itself it basically exits right there and snakes along the side of the rear head into a clip that holds it up there. On both cars i felt with my left hand until i found where it came out (its the only slinky feeling hose in that area), once found i pulled/wiggled it around with my left hand while going under the two intake tubes with my right hand which will locate the actual connector. At that point its still clipped up so you can release the clip if you can manage blind or yank it off (a bit reckless but still works lol). If you still have trouble its easy enough to remove the entire intake and upper airbox assembly to actually see it pretty easy. After its undone from the little plastic bracket you can then pull either side up enough to do the tests. 

He had recently done the knock sensor "hack" to run both banks of knock sensors at the ecu from one signal. Ive seen many others do this as well. 

 i ran the bank one wire to the sensor, went back to my ECM and cut bank 2 and tapped it into bank 1 there so the wire going to pin 27 on E4 was now feeding both pin 27 and 28.

On to plan B, splice the wires at the ECU in the passenger cabin so that pins 27 and 28 are getting signal from the single sensor on Bank 1 which cleared the light, allowed me to pass emissions, and restored power that I kinda forgot was gone.

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 basically splicing both ECU KNK inputs off of one good knock sensor/sensor circuit and fooling the ECU into thinking it is still seeing both sensors.

I have a 3VZ V6 pre-Taco that had a KNK code. I didn't want to pull the intake manifold off so i bought a sensor and pigtail from the dealer, plugged it in leaving the original stuff alone, and mounting the replacement sensor externally. I welded an exhaust stud nut (same thread pitch as the sensor) onto the engine "hook" bracket that bolts to the cylinder head. Its worked ever since and the truck actually feels stonger ( probably due to less ecu retard?)