2004 Lexus RX 330: Check Engine Light, VSC, & Trac Lights all are on.

I've taken multiple steps to turn off the lights, which most will work, but then the light comes back on almost immediately with driving.

The steps I've utlized include about 6 videos from YouTube subscription channel "proclaimliberty2000", such as: saran wrap gas cap/clean it/etc., checking all fluids, tire pressure, disconnecting battery, hold Odom button to clear the lights, use the Trac button method, etc. I even tried the Yaw Sensor Calibration which was titled " (Part 4) How To Fix Your Check Engine, VSC, Trac Off Warning Lights With Zero Point Calibration". I do seem to recall parking on a fairly steep hill when these lights originally came on, which is awfully coincidental. Again, ALL of these solutions worked with turning off the lights, but the lights come back on within 2 minutes of moving/driving the car.

** The only option that is still 'open' is replacing the gas cap which will be here tomm.

I ran codes at local parts store and my own cheapy OBD2 scanner, and both came back with ***************P0327 - Knock Sensor 1 Circuit Low Input – ( Bank 1 or Single Sensor ). I'm up against a wall with options and besides the pending gas cap, the last option seems to be to replace this sensor ( which I can probably do, but it is on the very edge of my abilities ). Additionally, the price for the sensor ranges from about $65 to $250 at local parts stores depending on brand. Any other suggestions ?

 

Hi Dayman6,

Welcome to Club Lexus and your 1st Post!

I had this happen to me and if I remember correctly, when the knock sensor code was triggered I got the check engine lights and car ran in limp mode.

There are two failures on our cars.
It can be the knock sensor or the knock sensor harness, sold separately and require removing the intake manifold to install so I will be installing both when the time comes.

Many people have had quick failures with aftermarket knock sensors and had to do the job twice which is why oem only is preferred, straight from a a trusted dealer and not a fleabay clone from auction sites.

When mine failed I did the well known hack of unhooking the failed knock sensor bank's wires and splicing them onto the good knock sensor wires.
This gets me by for now until I either hire someone to install new sensors and harness or do it myself, ugh.

It was easiest for me to do it at the Engine Ecm location which is located under the dash.

All I did was cut the knock sensor wires from one bank and splice them to the knock sensor wires on the working bank,
Another words, I spliced my knock sensor wires from bank 1 onto bank 2 so they share the same "good" sensor and get no codes or limp mode.

Knock sensor bank 1: KNK1, connector E-9, pin 1, black
Knock sensor bank 1: EKNK, connect E-9, pin 28, white

Knock sensor bank 2: KNK2, connector E-9, pin 2, red
Knock sensor bank 2: EKN2, connector E-9, pin 20, green

Do at ya'lls own risk!

PS- for anyone following along, this takes basic electric skills which you should have to attempt this and the battery should always be disconected before messing with any wiring.

(posted in fair use for commentary and discussion)

 

Awesome ! I really was not expecting such a thorough explanation and it is VERY much appreciated.
Yep, I'm leaning towards doing the bypass and am comfortable with the job and the risk for my situation.
Thank you for the reminder about disconnecting the battery, I could see myself forgetting...
My code is P0327 Knock Sensor 1 Circuit Low Input for a Lexus RX 330
Questions:
I got a bit confused on the repair portion of the diagram. Are you saying the following ( how my brain works ):
Cut black and white, and terminate/seal/cap the wires individually at the connector ?
Then take the 'live' end of black ( coming from the Knock sensor ) and splice into Red,
Then take the White ( from Knock sensor ) splice into Green ?

Knock sensor bank 1: KNK1, connector E-9, pin 1, black
Knock sensor bank 1: EKNK, connect E-9, pin 28, white

Knock sensor bank 2: KNK2, connector E-9, pin 2, red
Knock sensor bank 2: EKN2, connector E-9, pin 20, green

 

I would need to dig into the manual to see but if I remember there are a couple different knock sensor codes. Basically a knock sensor code means failed sensor or bad knock sensor harness.
The harness is a short junction of wires that hooks to the sensor and plugs into the main wire loom and they fail too.

When I looked into it, most all shops go straight to these failure points and if that doesn't fix it, get the check book out cuz now the code is meaningless and it's something unforeseen like wires eaten by rodents in the dash or up in the engine, etc. lol

When I was researching knock sensor codes, that what I saw posted in forums- just put the bad bank sensor wires on the working banks wires so they share the good sensor, so I did it and it worked.

It looks like you are correct, if when down in there if anything looks off, please post, wire colors should be exact and connector should match 100%.
If it wasn't behind the glovebox I'd have a look to confirm so I have to go off of my pics.

"Cut black and white, and terminate/seal/cap the wires individually at the connector ?
Then take the 'live' end of black ( coming from the Knock sensor ) and splice into Red,
Then take the White ( from Knock sensor ) splice into Green ?"

Yes this looks correct.

Cut the wires for the bad bank coming from the Ecu and cap them - BUT- leave a few inches if you can so you can splice back in when you get around to doing the knock sensor replacement- goal is to be easily reversible.
Now that the bad sensor wires are capped at the Ecu, take the wires coming from the engine and splice them into the working sensor, you wire colors look correct.

 

Got the gas cap today. I put it on, cleared the codes ( using OBD 2 Torque plug in with bluetooth to phone ), but codes came back within 5 seconds while driving. May ask Advance Auto to clear the code with their machine and see what happens.

Also going to throw in some octane booster for good luck, and drive it for a bit. Doubt it will work but I suppose it won't hurt. I concur, it is either the sensor or the wiring harness. Lats option is this bypass/wiring method.

Doubt if I can spend the $$ to fix it right, especially given it needs a timing belt change, a manifold gasket leak ( could fix when do the knock sensor ). That puts me in at about $3k. Then there is the issue of replacing the plugs and everything that will crumble when I starting moving things around ( sounds like my plumbing projects...). Its a bunny hole I'm not sure I want to go down or have the time for. I'm a novice beyond brakes, oil / routine repairs, but can turn a wrench/learn and have done so many times.

The bypass method is going to be the sweet spot for me for awhile. Then if I get the nerve up, will do the knock sensor & harness. The timing belt is beyond my comfort level and temperament for sure. Thanks for the help and letting me vent a bit !

 

Gas Cap replacement didn't work with keeping P0327 code away ( cleared and came back ). Octane booster actually did help it run better, but overall it is still definitely in Limp Mode.

In the meantime, I watched YouTube video for a 2005 rx330: but it was with the other sensor ( P0333 ). Youtuber did the bypass method as well, but cut Red Wire and spliced the Red ECU Plug end into the Black. Then 'capped' the red wire that had come from the engine. ( I think I had this mixed up before ). To reiterate, the Red coming from the ECU Plug is spliced into the Black wire. The Red wire from the Engine is now terminated. The video can explain it better than me. He suggests that if its the other knock sensor code P0327, ( in my case ), to simply do the opposite of what he did.

Therefore, I would be cutting Black, and splicing it into the Good Red. Cap the black that came from the engine. The Red wire is now sending a signal to the Red AND Black ECU Plug.

I understand there are no guarantees, and I might fry something, but wanted to ask you if this approach made sense to you. He skipped the second step where the white is spliced into the green. You are much more knowledgeable of this than me and yes, I'm taking baby steps and timing it with my schedule and courage...

As always, appreciate the insight...

 

The 2nd. Diagram is my proposed Fix for P0327.

 

Hi Margate330. I put up two Posts on 9-19-23 but wasn't sure if you received notice of them as I think I replied to my own post ( infamous user error ).

Anyway, if you happen to have time, can you look at those 2 posts from 9-19-23 and let me know your thoughts ?

Thank you much for any help.

 

Hi friend, sorry for the late reply.

I have been working around the clock with only time to sleep.

I jump on here to do quick posts but that's all I have been able to do.

I will try to look at your ideas tonight and compare with wiring.

 

No problem at all ! Take your time, I need to get it right after trying all other crazy options but chewing gum and rubbing my belly at the same time.

 

Hi Dayman6,

Your work looks correct to me and the youtuber's work you drew out on the paper looks correct for his code too, since it's reversed.

I went ahead and double checked, your code from post #1 is definately bank 1 knock sensor, just wanted to make sure and confirm in my manual.

One question:

As we know, each knock sensor has two wires.
The drawing you did only showed moving one of the wires(KNK1 to KNK2).

I moved both on mine.
So for you code I believe it would be moving the white wire(knock sensor 1, EKNK) to the green(knock sensor 2, EKNK2).

If the guy in the video didn't move them both, maybe it's not needed so plz let me know what you figure out.
It's possible the EKNK & EKNK2 wires are already internally jumped inside the ECU and they didn't show it on the drawing.

I'd move just the one wire like the guy in the video did first and try that.

 

have you checked the wiring in the engine bay? do you have an inspection camera to try and check the wiring at the knock sensors in the valley? i had this issue during covid when the weather was cold. i started the car and it was in limp mode, the CEL came back with a knock sensor fault. when i checked the wiring, a mouse nested in the valley and chewed up all the wiring. the insulation on the wiring harness is soy based so attracts rodents. i had to take off the intake manifold and plenum to access the valley to repair all the wiring.

have a look in the engine bay first, your issue may be obvious.

 

Great idea. I do keep it outside and it is not driven every day, so its possible they are eating those soybeans !

I'll troubleshoot this idea and see if there are any others before I go to splicing the the ecu/glovebox area wires.

I have made a mental note that our yukon engine bay has enough room in it to fit 4 large suitcases, and thus easier to work on / in / around ! Especially for those of us not quite as nimble as I was in my 20's...A wise man once told me never buy a car you can't change the spark plugs on (without taking apart 1/2 of the car, wiper cover area/etc./etc).

Happy to absorb anyone else's ideas, but I did troubleshoot quite a bit/explore other options ( see original post ). So I'm getting to the end I believe.

 

Just finished the splice technique outlined in my below handwritten diagram. Hopefully this will help someone else -

It worked ! The lights immediately cleared and vehicle is running fine, no limp mode. .

If/when the other knock sensor goes out, guess I'll replace them both at that time. Until then, thanks for all those that contributed, special hats off to Margate330.

PS - as I was removing the glove box, I checked the interior air filter, and it appeared to have NEVER been changed. Clogged to the max...

 

glad you sorted it out... when you are due for plugs, you will have to remove the intake anyway and can inspect and just replace the sensors while you are in there...