DavidinCT

Hi,

I am hoping someone could help here and lead me in the right direction. The other day, I changed a VERY dirty Air Filter, the next day after driving it for about 60 miles or so, I started to get a major loss of power. It seems like I step on the gas and it just crawls slowly, then pops in and seems fine but, I get some almost studdering. After driving it for a while the CEL came on, checking it gives a P0325 - Knock Sensor 1 Circuit (bank 1 or single Sensor).

I put fresh gas in from a good place, I cleaned the MAF, I also pulled the battery for over an hour in testing to see if it helped with almost no change.

This is very noticeable, and I need a car to get back and forth to work so, is this a big deal ? Will this just get worse or do deeper damage to the car ?

Also, if it's a Knock Sensor are these a DIY thing to swap out ? Does anyone have any detailed directions to replace them ? Should I be looking here first ?

Thanks in advance !!!

DavidinCT

So, after searching here, I used some Sea foam and after 50 miles driving, no real change...

Anyone help ? I found the OEM knock sensors for under $40 each, so parts don't seem too bad. What is involved in replacing them ? Is this a DYI thing or is this a very complex job ? Is there any directions anywhere ( I have not been able to find them)

Driving it seems ok once I get up to speed but, giving gas can be choppy and a major delay sometimes (yea, I know it's drive by wire and always a slight delay but, this is bad), I did get one real jerk when trying to give it gas.

Can anyone give me some ideas on this problem ?

Bocatrip

"Intermittent loss of power" is the name of the thread I started awhile ago. Reading may be helpful. This problem is more common than owners are aware of. Drive by wire components must be in the failure mode when checked by a mechanic in order to make the proper diagnosis. I believe there are around 4 different parts incorporated into the drive by wire system. Any one or more of them could be a culprit or possibly something else. You need a trustworthy Lexus oriented shop to help. I gave up as my problem is very intermittent and I have learned to live with it. Good luck my friend. Let us know how you make out.

DavidinCT

Thanks for the thoughts..

I'll look over the thread. I notied that you didn't have a code come up (I saw that one person replaced them). Mine shows a code of P0325, So it's claiming the Knock sensor.

I am really wondering what is involved in replacing the Knock Sensors. If this is the problem and they are under $40 each, so if it's an easy job, I will replace both of them but, I have no idea on where to start with it.

This was one day to another, strong car, no problems with it and the next day, the code comes up and now the lack of power...

For the record, my car has 226,000 miles on it....first time I have seen a problem like this.

rkw77080

P0325 indicates that the knock sensor #1 is not sending any signal to the ECM when the engine speed is between 1,700 - 5,400 RPM (the ECM uses the "knock" to adjust valve timing). Your sensor may have gone out coincidentally, but more likely, you may have worked some wires loose. Please take a look at the attached troubleshooting procedures before you decide how to proceed. I can tell you that replacing the knock sensors is not an easy task. It involves taking the air intake plenum out to get to them.



I would also check to make sure all of the vacuum hoses have been properly re-attached.

DavidinCT

Thanks !!!

So it's possable a hose got loose that could be causing this. The day before I swapped out the air filter before this started I'll pop the hood and pull of the motor cover when I get home tonight to make sure nothing got shifted off as for cables and hoses. I dont see that being it but, it's worth a look, it would be nice if it was...

Crap, does not look like an easy task if it's needed.... $40 part and $300-400 in labor to replace it.....Great. Not something I think I could tacke myself if I need to replace it.

Thanks again for your advice !

911LE

Pulling the intake off isn't that hard. When I pulled mine the hardest part was getting all if the wiring connectors disconnected. My fingers were sore for a few days! If you do tackle it you will need a T45 torx bit for the intake bolts.



That's one of the knock sensors in the middle on the right side.

DavidinCT

Is there a step by step anywhere for it ? I am not a car expert by any means so to save $300+ I might be willing to give a it a shot but, would need detailed directions....

What other parts do you need, just the knock sensors ?

Thanks for the advice !

Bocatrip

Personally, I do not think this is a job for a novice regardless of how much money you would like to save. If you have issues or mess anything up, the cost might be considerably more than just giving it to a shop.

911LE

I'm sure someone can post the section from the service manual. If not I can list the steps for you. Your problem could be the sensor itself or the wiring.

rkw77080

Take a look at these drawings - enough details to get started? Please note the non-reusable gaskets.

DavidinCT

Thanks, Not sure I can handle that one as I am no car expert. Does anyone know what the estimated time to do the job for a shop to do it ? Is this like a 3 hour or a 6 hour job ?

I will print this up and look over the car in detail with bolts, etc to see if it can be done with my skill set...I don't see it tho..

Trying to get an idea on what it will cost to have a shop do it, just in case... Crap

BTW. Does anyone know the part numbers for what is needed here.

The 3 gaskets and the Knock Sensors them self (is L or R different ?)

911LE

I'm not sure what the book time is but it would probably take me about 2 hours to remove and replace the intake. Fixing the knock issue would take more time (testing sensors, checking wiring, etc). If either you or a shop does it I would also recommend removing the throttle body from the intake and cleaning it throughly with aerosol cleaner. This will require a new gasket as well.
If it was my car and I was doing the work I would also remove the fuel rail and injectors from the intake and replace all of those seals as well (4 per injector). Mine were hard as a rock with half the miles of yours.

DavidinCT

I looked over the car last night, No lose cables or hoses, it seems pretty solid in there over all.

I wish I knew more about this process. Even replacing the Knock Sensor looks like it could be hard because of the PDF, Is there more detailed instructions to do this ? Not sure abour heavy testing, I would go in, check the wires for breaks, or damage, if I dont see any, I would just replace the sensors.

Anyone have a part list so if I look over it this weekend, I will have to order parts. Not exactly sure on the gaskets I need and I DONT want to order the wrong thing.

I am a PC tech who does pretty deep level stuff, so as I am a little freaked about about this, I bet I could do it but, I kind of need a little hand holding directions to do it.

Edit: I called my local shop that I have been using for a while, reasonable rates and they know their crap. Waiting for a call back to get an idea on a cost.

Tom57

Read this thread too ... it could be a wire connector to the sensor. > https://www.clublexus.com/forums/ls-...or-hack-2.html