Bullitt180

Hey guys, been having problems with my 2003 GS430. Kept getting error code P0325 for knock sensor bank one. Replaced both knock sensors today and the car ran great for about 15 minutes then CEL back on and now is throwing P0325 and P0330 for both knock sensors. I checked the wiring when I was in there and everything seemed fine. Does the 2GS have a separate knock sensor harness that can be replaced? I know other Lexus vehicles do but I couldn't see another connector to isolate the knock sensor harness.

UPDATE, READ BELOW!!!

Jackie939

Which Knocks did you use? and Where did you get them? OEM or Equivalent?

Bullitt180

I didn't spring for the OEM sensors, they were just too expensive. They are just model specific no name eBay sensors. I'll probably order OEM and return the no names. I doubt that is the problem though. Also I can't understand why after I remove the battery cables to reset the ecu, the car drives flawlessly for anywhere between 5-15 minutes, then the CEL comes on and the car runs like garbage and throws those codes. If the knock sensors are bad, why would it run so good at the beginning after every reset?

Bullitt180

So today I put on my Junction Produce mufflers (previously just had stock mufflers cut off), and after driving for a while I turned the car off and restarted it a bit later to clean the interior with the radio on. After a few minutes, I noticed the check engine light as well as the VSC/OFF lights had gone away. Haven't had much time to test it, will in the next few days. In my mind, these lights shouldn't have anything to do with the mufflers, but the lights have never gone away unless I clear them, this time they went away all by themselves and haven't come back on yet.

I need some input from a Lexus Tech. I know we have some on here. Could the cut off mufflers have caused some sort of problem that in turn may have caused the knock sensors to read funny?

i ride

To answer your first question, if its same as 2001, which id assume so, no you cant replace a seperate harness. Theres bogus info somewhere that says you can, and I went on a wild goose chase for a harness that doesnt exist. It was so long ago i forget what brand i used. i thought it was OEM equivilent. def not from a dealer nor ebay. Rock auto maybe ? i forget though.

mkshift

I'm currently experiencing the same issues, I had a P0325 generic knock sensor code Bank 1 popped up a while back. I ended replacing both knock sensors (with OEM sensors) and also checked out the wire connection, everything seemed ok. The car was all good and driving without any issues for a few months after replacing the sensors. Just within the past week, I've been getting the same P0325 code. I'll clear the code and the car drives fine until the code comes back on, usually within the same day, while driving on the highway around 60-65 mph.

I can't see the knock sensor failing after only a few months. I've been searching the forums but couldn't locate any solid info, or diagnosis for the issues. Hope someone could offer up some help. Thanks in advance.

Bullitt180

Well another update, the CEL and VSC/OFF lights showed back up this morning, went away this afternoon and showed back up this evening. This is so frustrating because half the time the car runs like a bat outta hell and other times I almost have to floor it to keep up with traffic from a light.

I just need to know if taking it to the dealer is going to give me any more info than I already have.

badblackgs

iTrader: (1)

I've been down this road. ordered "o.e.m." knock sensors (thats what they were called). went round and round but still codes. replaced the harness with a custom made one. still same codes. pulled the trigger on the 200 something dollars a piece knock sensors from the lexus dealership parts department. and haven't had an issue since. that was a year ago. our cars are super sensitive to the piezo electric knock sensors toyota uses. So if you don't buy them from the lexus parts dept. don't bother. just my experience.

kevin3344

If you have the true OEM knock sensors from Lexus, it could be your harness. I've heard of others having problems with that. When the dealer replaced my knock sensors they replaced the harness as well. Haven't had an issue since, and that was back in November.

Bullitt180

There is no separate harness for the knock sensors on a 2GS (v8 anyway, not sure about 6cyl), so not sure what they changed.

I'm not convinced my knock sensors were even bad in the first place, and I'm not concerned with the fact that I didn't replace them with OEM units because I'm still having the exact same problem. When a knock sensor goes bad, it's bad, it doesn't go back and forth between working perfectly and then not working at all. Something else is causing my knock sensor codes to show up. The only other thing I can think of is wiring, but I saw no questionable wiring or connections and since there is no harness to replace, I'm kinda at a loss of what to do.

kevin3344

I stand corrected Bullitt, just checked my paperwork and they replaced the knock sensors and a temperature sensor? Not sure but when I got the car back all was well. I would spring for the OEM sensors and see if that makes a difference. Take it from me the dealer is expensive if you eventually have to go that route!

Bullitt180

I don't mind going to the dealer to diagnose the problem. I can fix anything as long as I know what the problem is, but I'm not going to pay for a diagnostic that isn't going to give me anymore information than I already have. I just wish I knew if the diagnostic is more in depth than your typical obd2 reader.

kevin3344

Yeah I get that, I don't think the dealer is going to tell you anything you don't already know. Take a look at this thread:

https://www.clublexus.com/forums/rx-...preciated.html

It's an RX (of course) but finally on the third time, using the true OEM sensors fixed the problem. Believe it or not that could be it. Keep us posted whatever you decide to do.

Bullitt180

Ya I'm ordering them today and we will see.

Jackie939

Correct, on the No Harness for the GS4.

Not so much for the Knock sensor..Knock sensor WILL go back and forth if Faulty or completely fail..