What is this sensor/plug

[Gold5th]

Ok.. a little history.. about 2 years ago the wife's engine in her 02 R/T was replaced due to piston slap... they forgot to put the nut on the alt stud/bolt that keeps the belt tight.. I fixed that as soon as I found out...

But I was under her car today, cause her oil was a little low (about 1/2 way through the "safe" zone on the dip stick). and I saw some oil marks where she parks... but since it's one the street, other people park there some times too... so i decided to put her car on ramps so I can clean her cai filter and check for oil leaks.. luckily no oil leaks... but I found a plug not plugged in on the front of the engine, right next to where the lower rad hose goes into the block.. above the front engine mount bracket..

I took pics, but I'm using my ftp program to download the fsm right now, but I'll upload pics in a minute... I tried to plug it in where it looks like it goes... but it doesn't want to "click" in and I don't want to force it.

now the car runs fine, no cel, no codes.. it's probable that the dealership left it unplugged.. but I'm wondering what it is...

Thanks.

[Gold5th]

http://support.figmentium.com/images/neonplug/IMG_3150.jpg
http://support.figmentium.com/images/neonplug/IMG_3154.jpg

there's the pics... bottom of the pic/just tothe right of my hand is the lower rad hose.

thanks again

[Gold5th]

Ohh BUgger.. the fsm chapter 9 says it's the knock sensor... HMMMMmm good thing we've only run 91/92(mainly 92) octane fuel in it... also helps the wife doesn't drive very hard... (I do though... I love the sound of WOT above 5500rpm :P ) but I don't drive it much...

[Gold5th]

I can't get it to plug in.. I can't see the sensor end what the pins look like, but they feel different than what the wire end plug looks like...

[dodgeneonACR98]

There should be a little red keeper on the plug in part. Unless it was lost when it was worked on. If it's on there it will keep it from going on. Locate the keeper and slide it out some. If that solves the problem of getting it to slide onto the sensor. Simply plug it in and slide the keeper back into the locked position.

Thats the best I can think to tell you man Good Luck.

[Gold5th]

I called the dealership yesterday that did the new short block, the advisor said well maybe the new block doesn't require a knock sensor, since it's not throwing codes... they would a needed to flash the pcm, or give me a new one.. and I don't remember anything about the pcm in the list of what they did.

But if it doesn't need a knock sensor why is there one there? I don't see any red keepers.. it's not like the ait sensor.. it's more like the keeper on the headlights, the little nub that stick up on the sensor and the U channel thing on the wire..

Can I remove the sensor and not have coolant or oil rain on me? I think if I pull it and see if it matches or not.. if not.. me thinks I'll go demand a new sensor for free... local NAPA wants $90 for one. The dealer said it would be $70-$120 to look at it.. WTF! He also said since it hasn't thrown a code, if I plug it in, it might...

[dodgeneonACR98]

Use a small mirror on a stick to get a look at the sensor prongs. Would sure beat pulling it out of the block to just have a look see. Iv'e got a 1st gen car but I will go out and see whats up on my car in the morning. Maybe I can look at mine and shed some light onto this for ya. Till then GL