dajain

Good Morning Lexus owners. I an new to the group and this is my first Lexus. It is a 2000 Lexus ES300 Platinum Edition. Yes, I did buy it for $300 because the transmission will not shift past 3rd gear and she wanted it out of the yard.

I just picked it up yesterday and noticed a "knock" coming from the motor. Ran the codes and found code Po302.

Found the #2 ignition coil to be faulty. First pulled the coil and spark plug. Found oil in the spark plug tube. Cleaned out and made mental note to repair leak later. Put back together, started the vehicle. Still knocking and code comes back. While running, I unplugged the #2 coil power wires. No change in motor RPM. Pulled the #4 coil power wires and RPM drop does happen. Shut the car off and swapped the #2 and #4 ignition coils. Started back up and pulled the #2 coil wires and RPM drop does happen. Pulled the #4 coil wires and no RPM drop.
Conclusion, the coil pack wiring harness is not faulty but the original #2 coil is faulty. Now waiting on parts to get delivered.

So, back to my original question. The transmission and shift problem. I have done a little research on this and I am hoping for the best mind you. I have read if the car's computer senses a lack of power coming from the motor it will put the trans. into a limp mode and only allow 1,2 & 3 gears to engage.

Is this true?

Any other ideas what it may be? The was parked over a year ago because of the shifting issue. It is not worth a new transmission as the car is not in immaculate shape. I figure maybe a good commuter car, first care, put it up for sale if I can fix it or part it out if it is a too expensive of a repair.

Of course I am hoping this is the issue, but know there may be solenoid issues, bad transmission, electrical etc, but wouldn't I get other codes then. Only one is the #2 cylinder.

crwys

You may be in luck. A miss fire will cause the car not to shift past 3rd gear. So I would reset the codes or disconnect the battery to reset them. Then start the car and let it warm up (it also won't shift past 3rd if its cold) and see if it will shift correctly.

or simply fix the problem now and see. It may pick up the miss fire code too fast for you to check and engage limp mode again, I'm not sure

dajain

So, the info I read is correct then. Thanks for the confirmation crwys! I have a new injector on it's way and I'll see what it does then. Until then, I think a tune up is in order. It has been sitting for over a year.

I would be tickled pink if a $23 part is all that is wrong with it.

wmj259

You could also fix the valve cover gasket if there's oil in the sparkplug chamber.

RXGS

iTrader: (2)

I'm not saying this is your problwm, but when my car wouldn't shift into its final gear, as if O/D was turned off, it was the result of the knock sensor

dajain

But it isn't the final gear as I have read it is a 5 speed transmission including the overdrive. Maybe I read wrong on that?

RXGS

iTrader: (2)

These are 4 speed transmissions, 5 speed automatics weren't around until 2002. Again, not saying this is the problem, but may be related. Usually when these transmissions implode, which isn't all that rare, they go completely, at least from what I have seen.

dajain

And it all may be related to the bad coil on #2.
No ignition on #2 causing the engine to knock.
Knock sensor is working properly telling he ECM something is wrong.
ECM puts transmission into limp mode and wont go past 3rd gear.
We will see

My thinking seems like this is self defeating. I would think it would limit the engine rpm's instead of how fast you can move. Who wants to run a knocking engine until redline to reach hwy speeds. Seems the engineers didn't think that one thru well enough. haha

dajain

Update.
Got the new ignition coil and installed. Battery has been disconnected over a week so no stored codes.
Started up and sounded good. No more dead cylinder. Drove down the road and it did shift into 4th gear.
Got to a parking lot and the "VSC off" light was on and check engine. Shut it off and reset the codes.
Started back up and drove home but no 4th gear again.
I have a freeze frame from my code reader. Here is the info I have:
Code P0325 (Knock Sensor 1Circuit (Bank 1 or single sensor)
STFT B1 (%) 0.00
LIFT B1 (%) 21.1
STFT B2(%) 0.0
LTFT B2 (%) 14.8
Eng. RPM 2775
Vehicle Speed 45
Fuel Sys 1 OL-Drive
Fuel Sys 2 OL-Drive
Calc Load (%) 37.3
ETC (F*) 194.0
STFT B1 (%) 0.0
LTFT B1 (%) 21.1

To my eye, it looks like everything is good to go. Doesn't mean I can't be wrong. My thinking is that I may also have a bad knock sensor.

Any more ideas? Any tests that I can perform before throwing parts at this car? It drives really nice, would kinda hate to part it out if it's an easy fix.

Thank for all the ideas!

RXGS

iTrader: (2)

dajain

But, also like I said, I don't want to just start throwing parts at this car hoping that it fixes the problem. I know for a fact that the ignition coil was faulty, so that got replaced.
There is no longer an engine knock due to a dead cylinder but the knock sensor code is still coming up.

BUT, if you look at the "freeze frame" data I provided, it shows that the code is showing up at 2775 rpm engine speed. In my thinking, this would indicate a VVT solenoid issue and the timing is not advancing as it should, therefor, causing a knock at "off idle" speeds.

After the coil replacement, it did shift into 4th but only once. After that one time, the car has not shifted into 4th anytime even after erasing the engine codes several times. In my mindset, this tells me that the knock sensor system is working and there is something else going on. It isn't just an intermittent issue that happens from time to time. It is happening every time it drives.

The true question is, what tactical troubleshooting steps can be made to fix this issue instead of the Bandaid patch that will just get you by until the light comes on again?

dajain

With this car being tied together in so many different ways, I believe if it was faulty knock sensor you would get a code specifically for it. Such as code P0330, which are for faulty knock sensors. Those codes have not shown up.

Again, what is a tried and true testing procedure to determine what is causing the knock sensor to give a code.

Hayk

iTrader: (1)

Why don't you test the knock sensor with a multimeter for resistance?

LeX2K

Can't they generate a waveform based on vibration an ohm meter will simply show an open circuit. You can bang them against something while testing for voltage to see if the sensor is alive but that won't tell if it is capable of outputting a proper waveform. Only way to test them properly is with a scope with the engine running. But the ECU does this for you if it does not see the expected signal it throws a code, not just when the engine is pinging it always looks at the sensor.

dajain

There are a few reasons why I am looking at the VVT system and being the possible reason for the code P0325. Granted, yes, it could be a knock sensor, but if it were a faulty KS, wouldn't it see this fault at all rpm ranges? The code isn't happening at low/idle rpm. Only 2500+ rpm.

So, that is reason #1 why I am thinking it is the VVT. In the natural state of running (idle) there is no need for the VVT. Once the motor is taken off idle and asked to produce some power or performance, the VVT system provides the proper advance to provide the power and performance. Without the proper advance, the motor is going to knock and it doesn't matter what motor it is. It used to be controlled by vacuum, now it's all computer, but the principle is still the same. No advance = engine knock. If ya look at the FF data, the code doesn't show up until 2775 rpm with a 37.3% load. Without advance, there would be no way the engine wouldn't knock. But, I would think I would get a VVT solenoid faulty code if that were the case.

Second reason is because the previous owner (single lady & mid 30's) may not have realized how crucial motor oil changes for this motor to run properly. The oil looks pretty dirty and she couldn't remember when the last change was. All other VVT systems I have seen depend oil clean oil and maintenance and I can imagine the Lexus is no different, if not pickier than standard automobiles.

I hate to do it but I am going to "Throw" a set of VVT solenoids at it. it is what makes the most sense in my thinking. I am thinking the knock sensor is working as it should and doing what it is supposed to be doing. Maybe I am over thinking the troubleshooting process but no true troubleshooting options seem to be readily available.

I do appreciate all the help and comments. Like I did say, I gave $300 for the car and don't feel like throwing a bunch of money or parts at it. That is why I am being picky about troubleshooting it compared to just throwing parts at it. I bought it to help the previous owner out with some money and don't really need another car. I would rather get the thing running properly so I can either use it or re-sell it. But if it starts looking too expensive, I will part it out on E-bay.

Once I get the VVT solenoids installed, I will keep ya'll posted. Thanks Guys!