toyo

I had a defective knock sensor on bank #2 last week, which was causing the OD to not engage. On Friday I spent the entire day tearing it down and replacing it and a lot of other items. I went ahead and replaced the other knock sensor while I was in their. Did the valve cover's, timing belt, etc. Put it all back together and it ran great. Drove it yesterday to my shop to give it one more look over checking the coolant level, oil, leaks and such. It was perfect, could not have been happier.

It is my son's car now. It has 360K miles on it and we decided to just let him drive it since I really could not get a good price selling it with that mileage. It used to be my wife's daily driver up until a year ago when I bought her an LS. I got home late yesterday afternoon after stopping and getting her washed. Ready to hand it back to my son in all it's reliable glory.

My son drives it to go meet up with some friends for dinner when he calls me and says the check engine light is on. He also states that he is going 60 MPH and it's revving at 4K RPM's. I was seething to say the least. I told him to turn around and come home and let me check it. Put my scan tool on it and lord have mercy the #1 knock sensor is inop. Yep, the one that had no problems but I changed it anyway since I was in there.

It makes me sick that I have to back in it again and swap it out. I bought them at Advance since they were a lot cheaper than the dealer. Advance has a pretty good labor warranty so they will reimburse me for my labor time with no problems. How the hell do you like that for luck? It was running so perfect!

JAB

It is not without reason that the old saying goes 'if it ain't broke don't fix it.'

PS I think you mean to say 'I could not get a good price given that mileage . . .'

toyo

Just finished doing some research on Sewell Lexus. They are showing 2 different part #s for the 2 sensors. Also, they have the Knock Sensor Harness for sale in the "Service" section. makes me wonder if this harness goes bad and they sell a lot of them.

carguy07

Yes, the harness goes bad regularly, and is often the cause of the problem. It's pretty common to just replace both sensors and the harness since you have to pull the intake to get to everything.

toyo

I was not aware that the harness goes bad on this particular engine. I did inspect it and nothing looked abnormal. The connector clips were good, the harness sleeve was still in good shape as well. Interesting....

hypervish

Look on the bright side, at least now you'll be able to get it done quicker since you've already torn it apart once!

LOL, sorry I tried!

salimshah

My feeling is that since the engine runs hotter than other engines, the harness is exposed to higher temperature. When my knock sensor failed, the harness felt brittle. The knock sensors passed the ohm test. My recommendation is to replace both sensors and the harness.

I always say, please use OEM senors on RX.

For knock sensors, you must provide the VIN to get the right sensor. Another reason to get OEM from dealer or someone who knows about the part and the vehicle.

Salim

toyo

Being a technician I have installed many many aftermarket sensors and have never had a defective one. I am very curious to see how the harness looks after closer inspection.

AKBimmer

I got my oem sensors off the net cheaper than the dealer, but I did go get a quote first so I could order the right sensor.

I've read a lot of stories here about bad aftermarket knock sensors, so I just bought the real thing. I also did the wire harness and bypass hose while I was in there. Mine has been working great ever since.

Lexusblack

atleast you tried. hope for the best

salimshah

I stand corrected ...
If any one buys non OEM they need to research on their own.
They should verify with the VIN number too.

Salim

RX469

iTrader: (1)

I'd like to know how this all pans out for you. Good luck,

toyo

Installed new OEM sensors and harness today. Had my son drive it about 75 miles so far. All the drive cycles are completed, so I think I'm good to go now. lesson learned on this particular engine. It really does not upset me that much. This is how we all learn.

I did notice a few things that have my curiosity going. Did anyone notice that 1 out of the 6 injectors is different? The nozzle/tip is totally different. I have never seen this type of setup before on an engine.
This is a big one here.... On the lower intake manifold you have all bolts except for two nuts. The 2 nuts on mine were 13mm instead of 12mm like the bolts. Now, I have been working on Toyota's, Lexus's and most other Japanese cars for a very long time and have never seen them use a 13mm.

Nobody has ever laid hands on this engine besides me, I bought it new. This is so baffling too me. I need to pull out my service manual and do some researching. Anybody else have these 13mm nuts?