Recently, I performed an oil change and rotated the tires on my '04 2WD RX330. 3-4 days later, the Check Engine, VSC, Trac lights came on.

I had the code scanned with OBD reader and found P0328 Knock Sensor Circuit High Input. Code cleared, and within a day, the same lights came on. Subsequent scan pulled the same code. No codes found relating to VSC and Trac.

Coincidence that these lights came on at the same time and after my DIY job? Car actually drives fine. The CEL comes on right after starting, while the VSC, Trac lights come in a few seconds afterwards, but before I even put the car into drive.

Car has 75k miles on it. If it is indeed knock sensor, I will bite the bullet and do all of the following changes at once by mechanic: knock sensor, timing belt, spark plugs. If it's something I can try to resolve the current issue by not needing to perform these, I will defer these 'til they are scheduled (timing belt is 120k from what I'm reading).

Any feedback would be greatly appreciated.

 

Any chance of mice? Maybe the wiring harness to knock sensors has been damaged.

 

Sounds stupid, but check your gas cap.

 

Had similar re-occurring problem with my 05 330.

Replaced brake light switch few months ago and no issue since.

 

But, were you getting a P0328 error code? This is the first time this particular error code has come up. I have a hard time believing the brake switch to be the cause of this error. With the number of individuals who have had the brake switch issue previously mentioned, none have reported this error code.

 

Not sure about that specific code but when the Lexus tech hooked it up the code reader lit up like a Xmas tree. Said it was shooting codes all over the place.

May not be your issue but might narrow it down a bit.

 

I'm aware of loose gas cap causing CEL so I checked that even before getting code scanned. I've even filled up since so gas cap shouldn't be issue (unless they deteriorate or is broken/cracked?)

As far as mice - can't rule out anything I guess, but I don't have rat droppings in my garage to indicate a rat problem. Any pointers / pictures on where I should check? Don't even know where the knock sensor is.

Coincidence is the oil change - the only difference from previous oil change is I used a Pela pump to extract from dip stick. I did loosen oil filter a tiny bit before pumping (unaware that there is more oil leaked out of oil filter area until I looked under car after pumping finished). Flow of oil would not be in the way to ruin knock sensor, would it?

 

One quick way to ruin an O2 sensor or similar is to drop fluid on it while it is hot. If during your oil change you dripped oil in a manner to get to this sensor there is a possibility of damaging it.

 

If you want to elimiate the gas cap issue completely, I would try it with a brand new one.

The cap looks fine when the light came up and they replaced a brand new one (bad seal)

 

I am also experiencing a similar issue with my 2005 ES330. I have not clear the code yet, but I am noticing a high RPM ~3K on the highway when it's usually around 2-2.5K. Anyone figure out the problem?

 

Replace the gas cap, and check for disconnected or cracked vacuum lines, especially around the Air filter housing also check the operation of the purge valve and PVC valve