fatpc

I have the dreaded VSC and CHECK ENGINE LIGHT, I have read several of the other postings and seen this may be linked to O2 sensors. I took my RX to local dealership and these are the 3 codes P0505. P1135, P1155. I was told 2 02 sensors need to be replaced, bank one and bank two. I was told by the dealership that the Denso sensors were causing the problems and needed to be replaced with genuine Lexus sensors. However the lights are still on despite replacing with dealer parts. Rx is driving poorly, acceleration is bad, and poor gas mileage. Also it takes about 10 seconds for the car to start, but I just put in a new battery.

Initially, I took the RX to my regular mechanic and was told the VSC & check engine light was caused by bad solenoids, which I replaced to the tune of $1000. My mechanic stated the CPU needed to be reset but he couldn't do it & this is why RX was brought to the Lexus dealership.

So the solenoids have also just been replaced alone side the o2 sensors. Yet the car still running poorly and the lights are still on. I've just spent $1,600 on solenoids, two O2 sensors and a battery, RX has the exact same problems it had when I originally took it to the shop. I've only had the RX for 9 months now & it's been a rocky ride. I have another appointment with the dealership, but the dealership is the place that stated replacing the O2 with Lexus part would fix the problem. Any suggestions and Help would greatly be appreciated.

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carguy07

Reset, read the first code that pops up, report back.

fatpc

Carguy 07,

Thanks for your response, I have an appointment on Wednesday with my local Lexus dealership, I'll update you with the codes that are still present. The last time the RX was there they claimed the previously listed codes were caused by the Denso sensors and the codes would not clear until the sensors had been replace with genuine Lexus parts. Since I purchased the sensor from them I'm wondering what the new verdict will be, All I want is my RX running good again at minimum cost, since I've already spent $1,600 and the RX still has the exact same problems it initially had. I'll update you as soon as I know something,

Thanks again.

carguy07

Unless you had the wrong Denso part # (should be 234-9009) they are feeding you a bunch of BS. The OE Lexus part is a Denso and is the exact same thing.

salimshah

I would park the problem with the dealership and hold on the parts you had previously installed. Once the dealership fixes the problem you can insist that your sensors be put back and they restock the ones they installed.

Once you go the dealership, you are paying premium price and they should fix things properly.

Salim

fatpc

Hi guys,

Thanks for responding to my post, RX is still at dealership and codes are still the same, the first code is P0505 & two P1135 codes. Since I just replaced the o2 sensors with Lexus parts, the dealer is now claiming my ECU needs to be replaced to the tune of $2,600. Dealership is stating since the parts are replace with OE parts and codes won't clear it has to be the computer.

I just been out of 2k replacing solenoids, two o2 sensors and the latest was a mass air flow part which all was suppose to alleviate the VSC & check engine light. I don't have another 2k , so I'm in a tough spot, and of course may RX payments haven't stopped even though I'm occurring all these extra expense.

Dealership claims getting a used ECU from another RX is out of the question because I would need the key to the vehicle the ECU came from & even then it may not work. Either way, I don't have $2,600 k to spend. Any ideas? Thanks in advance for all your help.

Z07

Try the idle air control cleaning that is in the DIY sticky.

As with all codes clear them from lowest first as the fault may cause false higher numbered codes. So back burner the O2 codes until they are the lowest code present. For example, if the ECM can't control lean and rich via injector pulse because the IAC is not responding you could very well see a FALSE O2 code while the IAC is inop allowing too much air (lean) or too little air (rich).

Dealership obviously hasn't seen the eBay auctions for RX ECM's with master key included. You could, in theory buy a used ECM with master key included, then transfer the electronics from that to one of your master key shells so that it will work the locks and disarm the immobilizer. If it works then just get more masters cut or simply program in your old keys to the new master. The RFID for the master remote keys is embedded into the removable circuit.

But I wouldn't buy an ECM because I doubt yours has failed.

Figure out the IAC issue, check the integrity of all vacuum lines, check for an exhaust leak, verify grounds. I also would love to know how taking a Denso O2 sensor and putting into a Lexus parts box magically transforms it into something else. Exactly who does the dealer think made the sensors for the RX originally?

BTW a laptop and a $15 ODBII cable with included sample software will let you log the voltage from the O2 sensors and then load them into Excel where you can graph them to easily see if the precat O2s are rapidly switching lean to rich while the postcat O2 is lower magnitude and lesser frequency.

REF:

fatpc

Z07

I appreciate the through response, unfortunately the last word from the dealership was they got a trade in of Thursday that was same year and make of my RX and they swapped the ECU & my RX ran like it suppose to. Therefore, the dealership is adamant that the ECU needs to be replaced to the tune of $2,600.00.

The dealership also claims I shouldn't order an ECU from Ebay because it most likely will not have the master key & without the master key the ECU will be useless. I'm researching Ebay to see if I can find an ECU with master key as there's no way I would spend $2,600, after spending $2,000 on parts that probably didn't need replacing. If anyone know a solid seller on Ebay that I can obtain the ECU & master key for my 2001 RX 300 AWD, please let me know. Thanks in advance.

Z07

Sorry for the bad news. I do find it odd that the dealer tells you that YOU cannot use a used ECU and in the same breath tell you that they know yours is bad because THEY swapped in a used ECU.

kalali

I was thinking the same exact thing...

carguy07

Seems pretty far out there that a dealer would remove an ECM from a working car and risk plugging it into yours.

fatpc

Guys,

I agree the dealership been giving me allot of double talk, I finally convinced them to install a used ECU I order from Ebay with the key. The dealership claimed a ECU without the master key is useless because each ECU has a master key and the ECU would not work without the key. The ECU & key should arrive this week so hopefully this will solve this problem, not having a car for the last month been a really pain in the butt.

I still plan to take issue with the dealership on the 02 sensors because I was out of $463 for the two sensors and the parts didn't solve the problem, of course who's to say the solenoids had to be replaced either, since the ECU was giving off false readings & I repaired items based on what the dealership recommended & they based their recommendations on the codes the ECU presented. This has been one great big headache.

fatpc

I picked up my RX 3OO after the dealership installed the used ECU with key & they claimed RX was running like a champ. Left dealership & down the road the VSC & Check engine lights came back on again. So, I headed back to the dealership, they hooked up the diagnostic & now they claim the knock sensors need to be replaced to the tune of $1,100 & the knock sensor going out are completely unrelated to the work I just had done. The code was P330.

The dealership also refused to offer any kind of refund for the 02 sensors I replace unnecessarily. They took the stance the ECU was faulty & all the codes were false, but they had to go through the process of elimination to find out the ECU was giving false reads.

So I don't have too much positive to say about Lexus as a brand and now I have issue with the dealership customer service. I went with the RX because of it's solid dependability record and supposed great customer service, so far, I'm regretting my decision, my RX is turning into a money pit.

salimshah

I dont envy the position you are in.
So what is the guarantee that the current ecu is giving good readings?
I am surprised that the dealership installed a used ecu. Did you instruct them and tell them that you will pay labor and assume the risk (good/no-good).
I would pursue the un-needed/bad-diagnostic repairs ,,, be sympathetic but insist that the repairs were not need ,,, you may have to pay for the labor at the end, but you can tell them to take their un-needed part back.
When you bought the RX did it have the problems you listed? [did you buy your RX with existing problems]
Some one must have misinformed you that repairs are cheap on Lexus.

Salim

Z07

IMO put together a chronology and call Lexus USA @ 1-800-255-3987.