sibley

Looking for help!

My 2000 RX300 has codes P0171 (Bank one too lean), and P03330 (knock sensor bank 2).

Is there a way to narrow down which sensors to replace?

Could a too lean condition be caused by a bad injector or is it necessarily an O2 sensor problem?

Could the knock sensor code be simply an indication of knocking due to leanness and not really an intrinsic problem with the knock sensor?

I also cant get it into overdrive about 60% of the tiime. Could this be related to the problems above?

Thanks to anyone for the help.

Lexmex

Overdrive issue is probably something else.

Whenever I get a check engine light, I pull out the EFI fuse in the fusebox for about 10 seconds. Then go back driving, if it still comes on afterwards, then I investigate further.

I think you probably just have a dirty MAF sensor, but try pulling the fuse first (with the engine off of course), and then let me know if the light comes back on.

sibley

Pulled EFI and light went out for a few minutes only, then came back on. I then cleaned the MAF with brake cleaner and carburetor cleaner; it didn't look that dirty. Light is still on. Any suggestions on how to proceed? What can I start to do to diagnose the overdrive problem?
Thanks

Lil4cyl

I am also having the knock sensor/ overdrive issue. My knock sensors are bad, and my tranny will not shift into overdrive. As far as I can tell, the bad knock sensors are putting the computer in a "safe" mode and not allowing the tranny to go into overdrive so you will take it to be checked. The dealer wants $1104.00 to change my knock sensors. I am getting this done by another mechanic for half that soon.

Just a note, if your tranny is not going into overdrive, I have found a work around(temporary until knock sensors replaced). After you get up to cruising speed, put the tranny in neutral, cut the car off for about 5-8 seconds, restart the car, and put the tranny in drive. It will shift into overdrive then. Mind you, this is just a workaround until the knock sensors are replaced. Also noticed horrible gas mileage.... arouns 14-15mpg.

By the way, this is a 99 RX

Also, on the cutting off thing... make sure you are on a straightaway. The steering wheel could lock with the key off.... I usually do this after getting on the interstate, or on a long stretch of road.

sibley

Thanks for the info. I'll give it a try. It's good to know that the transmission may not be a separate problem.

flipside909

What type of fuel are you using i.e. octane? Just curious.

The 1MZ-FE V6 Knock Sensors do go out quite frequently for TRD S/C applied Camry & Solara models.

bored7one4

hey i have the same overdrive problem, and i think it the tranmission too but my knock sensor is also out so im gonna get it fixed today and see if that solve the overdrive problem.

How or did you get your Overdrive problem fix?

please keep me posted.

thanks

LexusSexus

Mechanical People, do you think if my tranny was replaced that my knock sensors would have been changed while they were at it too? Just curious as my mileage had greatly improved, I'm guessing yes

Lil4cyl

I have not fixed my knock sensor problem yet, but the tranny problem came witht eh sensor code etc...

I am just doing the neutral cutoff put in drive workaround until i get it fixed(within next 2 weeks or so).

From what I have read the knock sensors(there are 2) are located beneath the intake manifold and take some labor to replace.. hence the high price, plus lexus parts prices.. but I am getting a local mech. to do it for me for around $450.00.

bored7one4

i just got my knock sensor fix on my 00 RX300 which lexus dealers of westminster said that is cause of the problem with the reving and high RPM. Drove it home about 10 miles from the dealership on the city and freeway with the A/C on full blast and everthing seem fine, no reving or hesitation at all. I hope this fixed the problem so i would not have to worry about the car anymore. IF this problem still exist than i hope if show it ugly little head before the 70k mile warranty is up.

ill keep you guys posted.

Lil4cyl

Did it fix your overdrive problem also?

bored7one4

so far so good, it seem that the over drive is working and it kicking into the higher gear which there is no reving at all, 80mph is at 3100 RPM. I had two Mechanic told me that the knock sensor had nothing to do with the tranny but the guy at the lexus dealer said that if the knock sensor is broken than it would keep the car from going into the highger gear, that which would cause the reving.

Well hopefully the knock sensor was it and everything works good from now on.

ill keep you posted

flipside909

What octane are you guys using...for those who have the blown knock sensors.

bored7one4

i use 91, but i just got this car like two weeks ago, so who knows what the original owners was filling up with.

ArcherIII

It makes sense that if there was an issue with the knock sensors that the ECM would not let the tranny shift into overdrive, and it would retard the timing or increase the fuel mixture to a rich condition making your gas mileage drop. The knock sensors are of course listening for detonation and allowing the shift to overdrive would put increased load on the engine, making the detonation worse.

The manual recommends 91 octane but states that a lower octane can be used. I use 91 as recommended. The lower octane is probably fine under light load and cruise, but under hard acceleration it could cause knock which would the ECM to adjust. Again this leads to decreased performance and fuel mileage.

My first Toyota V6 was a 95 Camry. It occasionally had an issue with misfiring under hard acceleartion. Since the car was a short term lease I ignored it. Shortly before turning the car in I just so happened to be reading the manual to find out the fuel capacity. At that point I realized I should have been using premium all along. I immediately switched for what it was worth and the car then accelerated cleanly. Of course I cannot be certain that this was the problem but I suspect it was. Also many years ago a friend of mine had an issue with his Monte SS. I suggested he switch brands of gas since he had always purchased from the same place. Problem solved.