hugo2648

My 2000 RX300 now has 208K miles. And it is throwing the two Knock Sensor codes. It also pings under load. I do use regular 87 octane gas.

Questions:

1. Is it time to replace the Fuel Injectors. Does that help with the pinging? Generally what mileage should they be replaced? Are refurbished ones OK? What would be a good parts source? Should the fuel filter be replaced with the injectors?
2. The knock sensor code. Is it that the knock sensor is doing its job and throwing the code when it senses pinging ? Or is it that the knock sensors are bad? Several years ago, I did the hack to send the output from one knock sensor to both inputs in the ECU. Now, it goes into limp mode because of Knock sensors

maxSteel

Don't know why you are looking at injectors.

The error means the ECU is not getting a signal from the knock sensor.
The hack carried you on one sensor for a while but it is no longer. So either the last knock sensor has failed, the wire harness has failed, or the ecu has failed.

salimshah

With due respect are you letting your wish/hope direct your diagnosis or letting the evidence point you to area of interest?

Salim

hugo2648

I guess my main question is could it be the knock sensor is really doing its job and has not really failed. I ask because there is constant pinging under load.

I am thinking isnt that what a knock sensor supposed to do? To detect engine knock/pinging and accordingly put the vehicle into limp mode.

maxSteel

The knock sensor is a microphone picking up engine noises. There are always engine noises, sometimes the noises are engine knock pings.
The diagnostic says the code is thrown when there is no signal to the ECU with engine speed between 2,000 rpm and 5,600 rpm.
So it is essentially a failure to detect the normal engine noise. If it can't hear that it can't be expected to hear knock pings, so the code is thrown.

hugo2648

THanks. That makes sense.
What is a good online site that sells Lexus/Toyota parts of good quality and reasonable price?

Margate330

I agree with Maxsteel & salimshah.

If the knock sensors are working properly, the Engine ECM will advance and retard the timing to prevent knock and detonation.
With no knock sensor correction the engine can knock under different grades of fuel and dirving conditions.

This may be what you are hearing, knocking like crazy. haha

hugo2648

Thanks to all. Rolling up my sleeves to replace the knock sensors. The RX300 is fantastic. Has served me well. So much so that I became a Lexus believer and bought a RX350 for my daughter.

What is a good/great online source for parts?

maxSteel

I use RockAuto a lot, but I've also found my local Lexus dealer can offer good part prices online, often has free shipping, or I just go pick up
Usually it's a bit cheaper at Toyota dealers. It's a lot cheaper on Amazon and Ebay, but who knows if it's a knockoff part.

salimshah

Check out our DIY. There is a quite a bit of labor/love and I would not risk using suspicious parts. Do update it with part numbers and number of ground wires which are next to the firewall.

Salim

LeX2K

Assume every "OEM" 89615-12090 knock sensors on Amazon and Ebay are fakes especially Amazon. There are actual Toyota/Lexus dealers on Ebay those would be the exceptions. Toyota is flat out gouging for these now, they know you have to buy genuine. Try Amayama to save money.

Margate330

I will 2nd and 3rd this!

Ask me how I know. lol
My fake oem coils I bought on ebay was a nightmare for 2 years chasing down intermittent engine vibration(no codes) and elevated fuel trims due to weak spark.

Wasn't worth it!

maxSteel

Meant to add - before you start taking apart the intake might want to check the wiring where you did the hack, and verify continuity between there and the knock sensor wire harness connector.

hugo2648

Are Beck Arnley Knock sensors any good? The Toyota knock sensors are about $200 each.

LeX2K

Beck/Arnley doesn't make parts they sell parts from other vendors they are the box of chocolates in the auto parts world. Try them and let us know! Spoiler: you'll be doing the job twice that's always cheaper than doing it right the first time.