grumpyman

hi everyone, this is my first post. changing knock sensors in a 99 rx300. have replaced the sensors and am about to change the wiring harness. problem is i cant get the harness connector apart from the main connector at the engine block. have pushed down on this thing that looks like a tab on the main connector's housing, but no go. can anyone tell me the trick to this thing.

salimshah

FYI .. there are two types of knock sensors and my understanding is that each type has a specific wiring harness.

But you are still trying to pull it apart.

Do post your learning.

Salim

grumpyman

attached is a photo. don't know which type of harness it is. this is the end i am trying to disconnect

thomas1

wHAT happens is the plastic gets brittle over time and will not release. I suspect it will break when you finally get it released. There is a short harness that can be replaced which will fix this. I found taking a very small screwdriver and pushing on the tab will help by putting pressure on the grip.

grumpyman

thanks for your reply. i finally got it apart and did end up breaking the old one. no worries, finished the job reassembled everything, car seems fine. did notice one small detail--i have a missing vacum hose. i suspect the hose is still attached somewhere, but i don't know where to look. attaching photo of the emission control valve set mounted on the air chamber. the pipe with no hose is clearly visible. can you tell me where it goes or where i might look for the other end?

Lexmex

Hope this helps.

theLS400

would you have been able to just bypass the knock sensor in lets say a 90 ls400? or are they absolutley essential

Lexmex

That's a different OBD system you are talking about so I'd have no idea about how to do that specifically to that vehicle.

salimshah

I am in the middle of the knock sensor change.

Cant get the harness end off the retainer. [Disconnecting the connector was easy]. Will try again after I examine the new harness.

I have taken photographs so may be one of these days will do the diy.

I would highly recommend removing the cowl. wiper motor to gain access. The bad part is you loose tool tray [people who work on cars would know what I mean].

Due to heat the plastic clip of the harness just crumbled in my hand. Also the plastic box mounted to the valve cover, that holds all the wires going to the spark plugs and the injectors [#2,#4, #6] is falling apart. Does any one know the part number?

Salim

dennismtyl

would you have been able to just bypass the knock sensor in a 1999 Rx 300 awd. and do this without taking out intake?