scotty3318

Hi,

I'm new to the forums, but not on working on cars. This one has me scratching my head. I have a 2000 RX300 that has been parked for 5 years, (was my Mom's Daily driver before she passed) and ran fine before it was parked. Got it back up and going, (all new fluids and and a fresh tank of 93 octane) but on the first road test, immediately it was throwing a PO325 code for a bad knock sensor, and not shifting into overdrive like it had before being parked. When I tore the car down, I found that the crossover coolant hose had been weeping, and coolant was sprayed onto the rear knock sensor, and this sensor was indeed dead when tested with an ohm-meter. Front sensor was however good.


So knowing that the possible bad knock sensor will lock it out of overdrive, I ordered all the parts to replace them.

I replaced all of the following while apart for knock sensors.......
-both knock sensors (beck/arnley)
-knock sensor wiring harness (OEM Toyota)
-crossover coolant hose (OEM Toyota)
-lower intake gasket (Fel-Pro)
-upper intake plenum gasket (Fel-Pro)
-front and rear valve covers Fel-Pro)
-spark plugs (Denso Iridium)
-VVT-I solenoid o-rings

Once the car was back together I cleared the codes, bled the coolant system, checked for leaks, and let the car get up to operating temperature before leaving to take a test drive.

1st, 2nd, and 3rd gear come, but never shifts into overdrive. Check engine light didn't come back on for another couple of miles.

Stopped and cleared the CEL again, for the same code, PO325 and took off again. Once again, never shifted into overdrive. It seems to take miles before the CEL comes back on, but never even attempts to shift into overdrive as people have stated it will do after they clear the codes.

I'm not sure where to go with this one. Car runs perfect, and is as quiet as a church mouse, no lifter tick, no odd noises, no audible spark knock.



Why in the world am I still getting a code PO325, even after clearing the CEL, and why will it still not shift into overdrive?? Could the Overdrive Solenoid be stuck?

Any Help appreciated.

Thanks,
Scott

salimshah

Lock of overdrive comes after some driving. And it keeps coming back with shorter drives. At times the problem is actual knock being sensed instead of the sensor being bad.

Have some one look at live stream data.

I would have only used OEM knock sensor.

Salim

scotty3318

Do you mean locking into overdrive or locking out of overdrive?

I do know that the car will have to be at operating temperature before OD will work. I also read around here on the forums with people stating same issues, saying that when the CEL code is cleared their od would work for a short time, but then would result in a CEL upon the next complete stop, and then no OD.

My OD will not even work after the CEL is cleared at all.

Lexmus

Scotty,

Since you are only getting P0325, I would do the knock sensor hack shown here. This way you can determine if it actually is the knock sensor or something to do with the tranny. I did this for my P0330 code which is the opposite bank.

https://www.clublexus.com/forums/rx-...ck-repair.html

scotty3318

Thanks for the reply, not really wanting to hack up my wiring though. I highly doubt there is anything wrong with the trans, unless it is a solenoid that is stuck from sitting for 5 years. As I said, my mom daily drove this car and the trans never had an issue when we put it in storage. I have no problem at all with tearing it down to replace the knock sensor. It only takes an hour to get everything down to being able to get to them.

Just kind of puzzled as to why its still throwing a code after the sensor and harness was replaced with a brand new one, and torqued to spec. If indeed the POS is that sensitive to have to use an OEM sensor, I guess I'll order the newer revision OEM sensor with the "hole" in the end that screws into the block.

It's not my everyday driver currently, but it will be if I can solve this issue.

salimshah

That is exactly my thought .. the lack of OD is not due to the code. Specially when the problem is recent. I used to clear the code repeatedly and in 6 months or so the OD lockout started happening so frequently that I replaced the knock sensors.

Is the OD lockout switch pressed?

I still stand with my advice .. do a live monitoring with a skilled mechanic who can interpret the data for you. Just recently some one posted that OCV was causing his timing to change enough to cause knocking and the knock sensor code had come up.

Problem with diagnosing based on internet is, that at times clues take you in the wrong direction.

Salim

scotty3318

Salim, the "od-off" light is not illuminated in the dash. You can press it as many times as you wish, but no overdrive ever, just the light on/off in the dash.

That's odd on the VVT-I solenoid, usually when those have failed on my grandmother's RX or my coworkers ES300, the car had a random cylinder misfire on both.

salimshah

Before you get into total misfire, you start getting engine knock. If you catch my drift, I am trying to make you think with a clean slate .. without any preconceived diagnosis. With the closed loop system the problem can be anywhere. I do admit that there is an advantage looking at the existing/prevailing thoughts ... but you have already done that with the knock sensor replacement.

Salim

scotty3318

I understand that. Just speaking from my previous experiences with having two of those completely fail, not half fail.

maxSteel

The diagnostic guide clearly says P0325 will put the engine ECU in fail-safe mode.
It only lists three trouble areas

• Open or short in knock sensor 1 circuit
• Knock sensor 1 (looseness)
• Engine ECU

Don't know why it highlights "looseness" but it does.

Since it specifically indicates sensor 1 you could try that hack to use just sensor 2 at the ECU, even just to confirm it is not the ECU

scotty3318

So, I'd tap my bank 1 sensor wire into the bank 2 sensor wire, since bank 2 is currently the "Good" sensor, correct?

maxSteel

That's what I did (except mine was the #2 sensor)

I replaced both my sensors and the harness in summer 2014. Some time not very long after it started throwing a code again.
I held my nose and hacked out sensor 2. Hasn't thrown a code since.
Sometimes I hear some knock under load. Fixing it properly has been on my to do list forever. Doing the job is a pain

When I did the hack I used a quick-tap so I didn't have to cut both wires. Should be easy enough to reverse if/when I want to.
I know some people are opposed to quick taps.

When I replaced the sensors I found a mouse nest in there. I wonder if they caused the original issue and then returned to create a new one.
https://www.clublexus.com/forums/rx-...ml#post8241462

scotty3318

I've already replaced my sensors and wiring harness as well, and both were torqued to spec, 29ft lbs. And immediately I am getting this code for Bank 1 Sensor 1 as being bad.

I have no problem with tearing the car apart again to replace it if it is bad. It's just hard for me to believe that a brand new sensor out of the box is bad.

It only took slightly over an hour to get the car torn down to the point of the removal of the knock sensors anyway. (Not my first time tearing one of these down to this point, after 2 ES300 valve cover jobs, and this RX300 valve cover job years ago when my Mom was driving it.) The job isn't hard, just stupid if it's sensitive to an overpriced OEM sensor.

salimshah

Just keep in mind the possibility of the new sensor being bad too.
Salim

scotty3318

Yes that is possible, but man that would really suck.

Looks like I'll order the OEM Sensors.

Where's the cheapest place?