Hello, my 1999 Rx 300 engine light came on about a month ago. The ride almost feels the same except the tranny is a little sluggish, and it takes a while to shift into 2nd or 3rd gears at speeds around 30-50 mph, and the engine feels the same. I took it to the dealership, and when they finally came and told me the problem, they told me my piston rings, & seals were broke, and i needed a new engine and tranny for $13,874. I took it to another repair shop, they did research like crazy to find out the problem. They told me they strongly believe it's the Ecm but his answer wasn't solid Because lexus's diagnostic was so far off from what they diagnosed.

I did research Myself and in conclusion it Sounds like I have some sort of electronic/electrical failure (Ecm, etc.). Can anyone please help me and tell me what i should do Because that type of money for a car repair is crazy.

 

What is the mileage. Are you aware of the service history or is the auto new to you?

Usually, the problem is an input to the ECM, rather than the ECM itself.

As you have a "check engine condiction", may we suggest you stop by a local Auto Zone and have the error codes displayed and documented. Get back with us with those codes. This way, we have on board diagnostics assisting in the repair.

If you have a sludge condiction, I'm surprised the Lexus dealer didn't detect it. Does the engine smoke with blueish colored smoke. Broken rings causes excessive oil usage. Chances are, the engine won't run.

Have you had the transmission fluid serviced recently? When the transmission is slow to shift, is it cold ? Does it act the same when it has warmed up? What is the color of the fluid in the transmission. Is it dark, closer to black? New fluid is clear and cherry red in color?

Just a little clue, we use capital letters at the beginning of our sentences. This makes reading your request and reply clearer. Thanks..

 

hi the mileage on my vehicle is 80,000. Yes it is fairly new to me i had it for only a couple months.
i'll be sure to take it to auto zone tonight and get back to you soon with those codes.
I honestly have no idea why lexus didn't detect that when they took my car in the back and had me sitting there for 4 hours, they didn't even test drive it. There is no smoke or anything coming from the engine. Lexus should know the difference between a mechanical failure and an electronic/electrical failure.

I strongly believe this RX does not need a engine or tranny. I usually put midgrade 89 in my vehicle and yesterday i filled up with premium 92 and my engine light went off. But it came back on this morining. The ride is good until it starts to act up. (meaning trans sluggish shifting) that usually lasts for about a minute or less then its seems to be back to normal.
I've never had the tranny fluid serviced. Yes the tranny acts the same when it is warm.
thank you for responding i'll respond back after i go to auto zone and get those codes posted.

 

I'm back again and i finally went to auto zone and got the codes for my check engine light. P0171 SYSTEM TOO LEAN ( BANK 1)
AND P0172 system too rich (bank 1)

those are the codes that came back for my rx, and the guy told me that i needed 02 sensors. Is that correct?

 

Let me go over with you the P0171 & P0172 trouble areas:

P0171
-Air intake hose (usually loose or has holes)
-Engine coolant temperature sensor
-Fuel line pressure
-Injector blockage
-MAF sensor
-O2 sensor

P0172
-Engine coolant temperature sensor
-Fuel line pressure
-Injector leak, blockage
-MAF sensor
-O2 sensor

Under P0171, P0172, I would personally add spark plugs as I know some high altitude situations up here that we can get that issue on other vehicles. A loose gas cap can also throw a P0171.

What I would tell you to do first is either pull the EFI fuse in the fusebox in the engine bay (car turned off, key out of the ignition in the fusebox or pull the negative battery cable). Then let's see how soon the error pops up again and read the code.

 

well, as i was idiling last night i did notice that it was idiling like it wanted to shut off, but didn't. i noticed dark smoke coming from the exhaust, was the dealershi[p telling me the truth? what in the world is wrong with this rx?

 

The MAF or O2 sensors.

Your running rich, black smoke, and these control the fuel mixture. Use "Denso" brand replacement parts, as they match the Toyota originals.

First, I would purchase a can of MAF cleaner or electronic spray cleaner. There are good instructions in the forum on cleaning.

The O2 sensors may need to be replaced in pairs, located in the exhaust manifolds.

 

How long was that dark smoke coming out of the exhaust?

Tammy hit this right on point that if that smoke continues to come out and doesn't stop a little bit after you start up your vehicle, that the oil is getting in there and out the back of your RX. Just as Tammy mentioned this means seals and/or piston rings, though extremely scratched cylinder walls can do this on a smaller scale.

Motor oil doesn't burn like gasoline and that is making the air/fuel(oil/fuel in this case) mixture in this case incorrect, the combustion is off and thus it will definitely sound like it is about to die. Just enough fuel gets in there and your vehicle still goes.

I have seen this happen on a smaller scale with a few cars where the oil is filled way too much, but this is not the case.

The tranny may feel sluggish, but actually the inefficient combustion means you can't get going like you used to.

In addition, the O2 sensors will throw a light as they are getting fouled up with the oil.

If there is sludge, they can easily take a look inside by removing engine/valve covers and that doesn't take much.

 

thanks so much for both responses, and I realized the black smoke yesterday.
So the dealership may actually be telling the truth with the engine but the transmission, is another story. These posts were extremly helpful and very appreciated I'll absorb all this info and take it into the toyota dealership nearby today, hopefully they'll tell me a reasonable price and the truth, thanks so much guys. i'll reply in a couple of days when i hear an answer.

 

Is the air flow meter in the same category as the MAF sensor? I took my RX to the toyota dealership they told me it was the air flow meter and some other sensor dealing with feul, i cant remember the exact name but i will look at my paper work and let you know exactly what they said, but i'm wondering if it's sort of the same thing.

 

Mass air flow sensor and the air flow meter is the same part. The Denso part is dated and serial numbered.

 

thank you so much for all your help!

 

wow that was like watching a movie and not getting to see the ending please let us know what it ended up being? I hope everything worked out.

 

hi, it ended up being an air mass meter, and an air fuel sensor. When i received the car back it ran great again but the other day i saw dark smoke come from the exhaust again when i accelerate hard, and the engine llight goes on and off So i am going to take it back to see what still going on with this car.

 

i had the O2 sensors go out twice on my 1999 RX300. it did drive and respond like you discribed. it kinda ran like it was being flooded with too much fuel and the transmission would not ship at the right times as well.

about the engine, if you do have damage to pistons or other internal parts, there is a factory defect that makes the oil turn to sludge over time and therefore the oil isnt being circulated properly. lexus and toyota do not advertise this fact but they do recognize it. they extended the warranty on the motor because of this. if you do find that yours is starting to sludge up make sure you make them replace the entire motor with a new one! dont let them clean it up or rebuild it. as i am sure you know by now, if you complain enough lexus will give you whatever you ask for.

i had them replace my entire motor under warranty back in 2002 i believe. took them 6 weeks but it was done correctly. FYI the warrany extension is for all of the toyota 3.0L 6 cylinder motors used in that time period.

disco