mikey00

Knock sensor replacement will almost definetly fix your OD problem. By design the ECU prevents the trans from shifting into OD when you have a knock sensor cel.

BrianMyers

I just completed the huge task of changing both knock sensors in my 2000 Lexus RX300 and wanted to "give a little back" to the community and share a couple things about my experience because these forums were so helpful to me when I was doing it.

First off, I called a Lexus dealership in Las Vegas and had them run the VIN of my car. This told them the production date so they were able to tell me whether I had the old or new style knock sensors (thanks to MikeMacch's previous post for letting me know that there ARE two different sensors as I was unaware this was even an issue!). Turns out I had the old sensors (89615-12040) and was able to get them from an eBay seller for $110. These were OEM; from what I've read you DO NOT want to go with the aftermarket Delphi sensors. I picked up the sensor wire (82219-07010) and bypass hose (16261-20010) from Toyota for $60 (I overpaid but I was in a hurry so I had no other option!). I picked up the Fel-Pro gasket set from Napa and paid $80 for that, however you can get them online from numerous places for $50 - $60.

Lexmex

Just curious, how many of you who have had these knock sensors issues have been running regular unleaded?

mikey00

I am on my second RX with 157K on this one using nothing but regular. Never had a knock sensor issue or any valid CEL codes.

00GSRVTEC

This is a great thread. A co-worker told me his 99 RX300 won't shift out of 3rd gear which I am assuming is OD. He isn't mechanically inclined. He said it had a bunch of miss-fire codes.

I will hook my scan tool up to it tomorrow and see exactly what codes it is showing, but from his description and reading here, it is his knock sensors that are bad.

00GSRVTEC

What if the knock sensor is not throwing a code? The only codes coming from my friends RX300 are:

- P0300 Random Multiple Misfire on 2,4,6
- P0171 System Too Lean Bank One
- P0136 02 Sensor Circuit Malfunction (Bank 1, Sensor 2)
- P1150 Manufacturer Control Fuel Air Meter

Would these codes cause his RX300 not to shift out of 3rd gear?

I talked to my friend who works at Lexus and he said right off the bat that it was the knock sensors and that I should change the wiring harness as well.

Can I get any confirmation that the knock sensor would not throw a code and cause the symptoms?

Lexmex

Funny, I don't see the two typical knock sensor codes, P0330 or P0325.

The P0136 is not a biggy, that's the after the main cat code.

P1150 is actually the a/f sensor that's easily visible in the engine bay behind the radiator and on the exhaust manifold.

P0171 is basically a code that I like to call an accompanying code or it just came along for the ride do primarily P1150 and the P0300 code.

The one that is the likely culprit here is the P0300 code. Not sure why specifically you'd be getting it, but you could have an ignition coil on the way out or something dirty passing through that is causing troubling readings in the combustion, i.e. even diry plugs from foul gas.

What kind of fuel trim values have you been getting if available.

00GSRVTEC

Not sure of the fuel trim values. I will get my friend to bring it over and leave it with me so I can start diagnosing it.

I am confused about the no knock sensor codes either. I talked to a friend of mine and he thought it was strange too.

Lexmex

Forget the knock sensor and focus on that misfire.

absorbing

I just brought the knock sensor from e-bay, but after i get it , it seems not right, i know that has 2 versions my rx300 is year2000, the package is show right number but the enclosed parts does not look right, the parts show 71

absorbing

finally, spend 10 hours to replace it, thank you those diy information; my mpg go down to normal avearge! great!

kosogo

This is great. I have just bought a RX300 late 2000 with engine warning light on. I've checked it with a Lexus dealer and it turns out that it was the knock sensors. BUT according to Lexus they didn't think that both sensors would be giving an alarm at the same time. Lexus supected it to be something else.
I think i might just thrust you guys - and go ahead and change both knock sensors - to the "new" types - it might just be the sensor that wears out after some years (and considering the environmental temperature the sensor is in - it might just fail after a certain amount of time)

Lexmex

Welcome to the Club.

Generally, given the difficult getting to the area of the knock sensors, it's easier to change them in pairs. It would be interesting to know what engine codes came up for you.

salimshah

It could be the mini-wire-harness that connects the sensors to the main harness. As Lexmex stated, when you consider the time and money spent to get to these (sensor/harness), you might as well replace both sensors and harness. If you have not looked at the DIY, please do and add your experience there to enrich it.

Salim

kosogo

The knock sensor codes are P0330 and P0325, i zero out the codes frequently and the car runs much better for a while - but then the knock sensors are knoking on again :-) I have already ordered new sensors so I guess i will do the changeout once i have got all the parts - ned to order the harness and water hose though. I have also filled up the tank with 98 octane fuel - someone thinks that that will burn away some carbon deposits in the engine, causing the engine to misfire - I am not completely convinced but it is worth a try. Thanks for reply and i will tell you how it goes...