2000 es300 @ 145000 miles

I'm in college and I go back and forth to home on certain weekends which is about 200 miles one way. Each time I go home I would get CEL either going home or going back to school. Each time it would be coming from the knock sensors. After I get back to school from the weekend and a couple of days of cold starts the CEL would turn off. This has been going on for a few months already and I never feel that's there is anything wrong with the engine.

Sometimes the code would be P0334 (Knock Sensor 2 Circuit Intermittent Bank 2) and sometimes it would be p0330 (Knock Sensor 2 Circuit Malfunction).

As of right now I'm getting P0330. I've checked the voltage and the knock sensor does work appear to be working and I have no idea what else to do.

Below is the condition that tripped the CEL and the software I used was OBDwiz from scantools.

 

Your STFT is OK but he LTFT for both banks is absolutely out of spec (too high). For some reason the ECM is enriching (in long term) by 28% the A/F mixture. Find a skilled mechanic before start replacing sensors or other expensive parts.

 

Correct, those fuel trims are so high, I am surprised they aren't setting the engine light all by themselves... Most common cause for that is a vacuum leak somewhere... essentially, what is happening is that the ECU sees so much air coming through the mass air flow sensor, looks at a map and injects that amount of fuel, then, it looks at the O2 sensor reading and decides if it was correct or not, if it was lean, it adjusts the fuel trim percentage up (adds fuel), and if it was rich, it adjusts the fuel trim down (decreases fuel)...

Now, here is the deal - neither of those may have anything to do with why the knock sensor is acting up... That information above is just the general parameters that were going on exactly when the code was set... Knock sensors don't work as well when they are hot - they can literally break down this way... My guess would be that only on your long drives, the knock sensor actually stops working due to heat, but, after time on short trips and cold starts, it doesn't run long enough for it to stop working properly...

Knock sensors rarely cause drivability issues, unless they are reporting knock that isn't present - they are there to protect the engine from damage from knock, which can be caused by poor fuel quality (lower octane than the motor is rated for), excessive carbon buildup causing preignition, high intake air temperatures, and more. It is basically a sensor that the ecu looks at and if there is activity (knock) present, then the ecu retards timing in an effort to save the motor... relatively simple to replace if you can easily get to them, not sure where they are on the ES motors, but they are generally a 1 wire sensor that is simply screwed into the side of the block... 1 per set of cylinders...

 

http://www.findonefindall.com/toyota...ock_sensor.htm

Applies to the 1MZFE motor group.

 

Good write up on how to install/remove, I just hate how that guy writes... it is soooo annoying about how he feels everything should cost a dollar or two...

And, he writes about the Torx bolts to remove the intake manifold... heh, you could also just use a 10 or 12mm socket (whichever one applies) and do the same thing without a specialty tool...

 

I just remembered that Salimshah also did a knock sensor DIY for the RX300 recently,
https://www.clublexus.com/forums/rx-...ement-diy.html

 

I guess I will check the MAF reading from obd2 scanner next time the code trips. As of right now the CEL is off after just one round trip from my apt to school and back. I'm surprised it turned off so soon as it usually takes about a weeks worth of restarts.

Or is there a way that I can make the code trip be unplugging a hose or something to see that it is a vacuum leak?

And I forgot to mention that the knock sensors were changed about two years ago.