thomas1

Could be a bad VVTI timing gear assembly....Maybe the cam is not timing properly at different engine speeds.

tuanle785

ok so what started as a trans issue i thought turn out to be a main computer issue, the ocv I replaced and same thing so the dealer traced it to the ecu! now i just got a used ecu from lkq for 300 bucks.. I was excited as a ****.. then came to the programing the master key.. and oh man it started to add up real quickly, just sent my ecu to Sewell lexus from reading the forum here... steve a real helpful guy currently has my ecu and gonna flash it so its will be new so I can program it to my keys, and HOPE it is truly the issue. so i read the fourm and seen the process after I get my ecu back i just put my key in and remove correct? swelle told me I only have one chance at this and I do no want to mess it up. so anyone every did a 2000 RX300 new computer flash and progam please help. I should have ecu back by friday hopefully

mikey00

Here is the procedure to program the keys after a new ECU is installed (or reflashed) from the RX 300 service manual. I would expect Sewell to supply you with these being they are doing the reflash. Be sure and post back and let us know if the ECU fixes the problem. I still suspect it is engine related.

"IGNITION KEY REGISTRATION (IMMOBILIZER EQUIPPED)
NOTE: This procedure MUST be performed only when NEW Engine Control
Module (ECM) is installed. A new ECM is in automatic
registration mode, and up to 3 ignition key identification
codes may be registered in ECM at one time. In automatic
registration mode, the last ignition key to be registered
becomes the sub-key.
1) Ensure SECURITY indicator light is flashing. SECURITY
indicator light is located on center of instrument panel, just above
the air outlets above radio.
2) Insert ignition key into ignition lock cylinder. Note that
SECURITY indicator light should now remain on steady.
3) Once ignition key registration is under way, SECURITY
indicator light should turn off. After ignition key registration is
complete, SECURITY indicator light should come on steady. Remove
ignition key.
4) The SECURITY indicator light should flash when ignition
key is removed from ignition lock cylinder if registration is complete
and system is operating normally. If ignition key registration was not
completed with ECM in automatic registration mode, a code 2-1 will be
displayed by SECURITY indicator light. When inserting an ignition key
that is already registered, code 2-2 will be displayed by indicator
light.
5) If programming additional ignition keys, repeat process
starting with step 1). If additional ignition keys do not need
programming, procedure is complete. SECURITY indicator light should go
off once last ignition key (sub-key) is registered.
6) To complete automatic registration mode, depress and
release brake pedal at least 5 times within 15 seconds, or request
automatic registration mode completion by using Toyota scan tool
connected to Data Link Connector (DLC) No. 3."

tuanle785

ok swelle lexus call today they shipped out the reflashed ecu. anyhow on another note. the rx has been in the garage waiting on ecu with the battery unhooked. well today I had to take it down the road to run a quick task. anyhow old ecu is plugged in so i can drive well this was different ride becasue it shifted like it is suspose to so I got all excited and stop and go a few times to verify. went home and scanned and for the first time no error codes!! I was very excited drove around for a min. then scanned and still no codes. so i figured leaving the battery unhooked for a while reseted things. well an hour or so later went for a drive and scanned after wards and got same error code again 1656 so no I am convinced its not an engine or trans issue but a computer issue so that is good news but so far between getting used ecu, a few sensor and a OCV and sending it to get reflashed, i have about 750 into what I was sure an easy fix! well if it works when ecu gets back. I suspose its cheaper than a tranny replacement and I didnt even get dirty fixing it! but I will post as soon as ecu gets here so everyone knows if they ever ever happens to anyone becasue I sure did learn a few things! ha plus I have never heard of this issue ever and been around lexus and such for a while. fingers are crossed that the ecu is the issue and new one will fix it. till next time CL and thanks for all the advice. again i will post results of new ecu when it comes

tuanle785

in step 2 of the key programing. how long does the light stay steady cause im doing it now and its been steady for a few mintues now and i'm getting worried

tuanle785

nevermind it works! all 3 keys and car has no more trouble codes...yet..... drives fine and is doing what its suppose to! so it was a ecu problem so far.. on another note as i stated on an earlier post. after having the car unplugged for a day the old computer also was working popperly but it did have a check engine light on. so lucky it wasnt tranny or engine but I learned a valuable lesson. 1 . go get a popper diagnosed before buying sensors ect unless you know its what it is. and do your research. so buy doing this way my total after programing ect was about 700 bucks versus almost 2K plus at dealership. i wasted a couple hundred buying valves and things thinking it was something simple. anyhow ill repost if something else pops up ..thanks alos clubL

tuanle785

ok so after the last post it drove perfect for about 120 miles then I parked it and was in happy land for a min. then got into the rx after it rested for about 10 mintues and it started very minutely a little shake between 2-3 just a tiny bit but I noticed it, and it just got worst the more i drove in stop and go traffic, it was a lot less jerky as b4. then i parked it and unplug the battery. hoping it would reset anything or codes and drive correctly. well next day came and it did the same dam thing as b4 and with old computer! no i'm stuck with the same issue and at least I know for sure its not mechanical because after the new computer installed it drove so wonderful!!! I think there is something causing the computer to fail, but this rx has never been wrecked or tampered with. i've check all the bolts ect to see if anything has been lose or removed ect and no signs. I may just have to sell this as is becasue its still drives just got a shimmy here and there! i'm done taking to shops. already spent a nice chunk and got nowhere!! if anyone has any other ideas please do tell!!. it not timing nor anything related to tranny and now I know its not ecu issue its something causing the ecu to fail on both or something casuing the ocv sensor not to trigger and operate correctly. I took valve cover off and its very clean in there no slugging. is a shame to let this beautiful rx go to be a clunker but if its engine its not worth it because the value is not there! so i have to make some discussions asap fix or not to fix

Lexmex

The only other thing that comes to mind is you could be having a voltage dip or some grounding issue. Lexus should be able to run a diagnostic through it to check this, but otherwise it would be taking an electrical tester and going at a lot of electrical connections.

mikey00

I doubt very much your ECU is failing. You now have 2 good ECUs. I am still betting on something being amiss in your variable valve timing system. The system is continuously adjusting the timing and everything is working fine until it hits one certain point where the ECU detects an open or short at the OCV and triggers the code. You need to get cover off and completely check timing belt and related parts. You may want to re-read the link I provided you above where a GS with missing tooth on the crank sprocket was having this problem and code. I bet this problem was caused by service at one time most likely the timing belt change.

frankjames

How much did it cost to have the ECU reflashed??

flpulio

Looking for help on this topic for a 2000 ES300 V6. I've read through this entire thread and I'm thinking it's one of the OCV filters or OCV itself. Car started running terribly rough on my wife at around 45 mph after about 20 mins of driving, lots of shaking etc. I've replaced coils before and am familir with the misfire symtoms but this seemed to be something more intense. When I started it cold (Chicago in December) it was running fine.

Codes are multiple misfires, P0300, 302, 304, 306 but also received a:
P1354-bank2 (VVT Sys Malf)
P1150-bank2 (air/fuel ratio sensor range/perf malf)
P1351-bank2 (VVTsensor range/perf problem).

I bought this car 5 years ago with 90k and it might not have been maintained so well, there is more engine sludge thank I'm used to seeing so the filter and/or OCV makes sense. I found the OCV's on the top drivers side of the engine but can't find the filters. My cheapo haynes manual says there is one in each cylinder head. So that leaves me with these questions;

What does bank 2 signify? Is bank 2 the front or rear OCV?

Is there really a separate filter for each cylinder and do I need to pull the valve covers to get to them?

The pics of the engine above look exactly the same as my 2000 ES300. If so, I can rely on this post and assume it's the rear OCV (bank 2) and the filter is the larger bolt circled in white?

Thank you!!!

carlover

My post is a bit late for this guy, but I just followed this for my ES300 1MZ-FE so here goes for future trawlers.

Bank 2 is front (closest to the bumper, easier to work on) Bank 1 is the firewall. The pics for this RX300 seem to have them backwards...

Each bank has its own filter, not each cylinder - there are 2 banks = 2 OCV's and 2 corresponding filters. You do NOT need to pull the valve covers.

My 2000 ES300 is the same and it worked for me. Do NOT try and switch the OCV's for testing as they are different. The cams will not face the correct way as they are different parts.

Great post for the most part - I just think the bank #'s are swapped on the pic.

Pita74

My RX 300 has 125000 and the AWD transmission will not shift from third to fourth until it gets warm From that point on its fine and drives normally. Any ideas?

hypervish

That's normal. Please do a search. you will find more information regarding that.

Prjoel1

Hi my name is Joel. I own a 1999 lexus rx 300 awd. My problem is OCV, and other. I did a tuned up, also change shift sol A and I still trouble. SUV try to star but shut off immediately. It is possible that is out of time?