Scott R

Thanks everyone. I brought my car in for an oil change this morning and asked them to look for any loose hoses. They didn't think that was likely to be the issue (they are just a small repair shop but they had recent experience with another Lexus throwing the evap code, so I think they were guessing along the lines of what they just dealt with). So I don't know how well they poked around, but thanks to Coleroad's photo, I'll take a look myself today and will report back.

FWIW, I had my gas cap replaced at some point in the past. I honestly don't remember how long ago it was, who did it, and what prompted it. Pretty sure it wasn't a Lexus dealer, though, because it's not a stock cap (it's not "tied" to the fuel door anymore, so I have to hold onto it when I fill up).

Regarding the O2 sensor, someone gave me a link to the Denso one on Amazon and I have considered trying my luck at replacing it. I couldn't find a YouTube specific to the SC430, so I'd have to figure out exactly where it's located. But before I do that, I'm thinking of anonymously calling a CarMax in another state to see if I can talk with one of the guys who appraises cars and explain my situation and ask if they could give me a feel for how much having a CEL on would impact their offer, given the age and high-mileage and fact that they'd be selling at auction. My guess, though, is that I won't get a chance to talk to someone in that department, in which case my next plan is to try my luck at resetting the codes right before I have them appraise it. The paperclip issue will make that a larger hassle, though.

On that last note, texsexlex, I think the paperclip fix is for the VSC ON / OFF lights, not the CEL light. And, yes, my VSC ON / OFF lights are now on as a result of plugging in that code reader, so I do have to apply that fix.

Jabberwock

If a car you are selling or trading in has a defect, I suggest it is best to be upfront and transparent about it when selling or trading in the car (or have the defect repaired beforehand). I assume most people would not want a seller to have just cleared the error codes before showing them a car so that they find out after the fact that they were scammed. Karma has a long memory and never loses your address.

Scott R

Wow, you guys are the greatest. Special thanks to Kevin for recommending that I look for loose vacuum hose, to Bgw70 for pushing that point, and to Coleroad for posting a photo (since I have zero experience working with cars, other than jumping a battery). Sure enough, one of those hoses was completely detached. Photo:


After reconnecting it, I decided to disconnect my battery to reset things that way, rather than use my code reader, since I'm hoping this method will also clear the VSC ON / OFF codes. How long do I need to leave the battery disconnected?

I'm assuming my CEL will go on again because of the O2 sensor, but is there any chance that code was a false error caused by this? It just seems odd that I would get an O2 error code right after this one.

Or is possible that this disconnected hose could have caused my O2 sensor to fail? If not, any ideas as to what sort of damage/harm might have been done as a result of this hose being completely disconnected like this and me still driving it for a week?

Part of me is elated that I've actually diagnosed (with your direction) and repaired something myself, but now I'm also disappointed with what my wife and I refer to as "the boys" at the auto repair shop we've used for years. I specifically asked them to poke around and look for loose hoses and they either didn't bother to look or they somehow missed something that wasn't hard for me to spot.

On a semi-related note, my daughter's 2007 Jeep Patriot also has a CEL which also points to an evap leak. Weird, huh? So prior to this, the Jeep had a problem where when we tried to fill it up at the gas station, the pump would immediately stop as though the tank was already full. I ended up bring it to "the boys" who replaced the fuel filler. Then a month or so later the CEL goes on. They checked the code but suggested I bring it to a Jeep dealer because they didn't have the machine to do a smoke test. I ended up bringing it to another private repair shop that was highly rated and the guy calls me today to tell me that the smoke test indicates that the leak is somewhere around the gas tank and he would need to drop it (about a 3.5 hour job) to figure out exactly what the issue is. He said it was safe to drive, but would have to be fixed (or sold) before I had my emissions done. I explained to him about the fuel filler job and he did think that there was a possibility that they might have shortcutted that job and caused an issue, but he would have thought that the CEL would have gone on a lot sooner if that was the case. That Jeep has had one problem after another in the relatively short time we've had it and my daughter doesn't even drive it that often. So I'm also thinking about trading that one in for a used Toyota RAV4. But I'm leaning towards fixing this issue and crossing my fingers that we can get through at least another year before anything else goes wrong.

Scott R

Jabberwock, FWIW, I would never clear the codes and then try to sell it to a private party without telling them about it. I guess I feel different about trading it in to a huge car dealer who I know is only going to sell it at auction, where I believe auction buyers don't usually have a chance to fully inspect a vehicle anyway, and so are essentially buying it as-is. Also, clearing the codes would still allow someone to plug in a code reader and see that it wasn't ready for emissions, which would tip them off to the possibility that the codes had been recently cleared. My other reason for not feeling too guilty about it would be because I know they are going to offer me considerably less than it's worth anyway, and the O2 sensor can be purchased for less than $100 and installed in less than an hour (based on my YouTube watching). But I do appreciate your input and perspective.

mandyfig

Reminds when I bought my SC back in 2010, I had the VSC lights on. Part of the purchase deal was to get all lights addressed and OFF and other things (wish list). The used car dealer did address, by sending the SC to the closest Lexus dealership, which reflected on the Service history, I learned about it when I checked the service history.

I agree that if you are selling a car, either the disclaimer is very clear or else, car is in good working condition at the time of sale. Do unto others...

Coleroad

on the jeep, those are symptoms of a bad the purge vent valve ( part of the evap system). Not sure how much of a job it is on that jeep, but I would assume my what you were told It does require the tank to be dropped.

Jabberwock

This thread is seriously off course but unfortunately I feel compelled to reply given my role and forum responsibilities. I apologize if my comment seems overly sanctimonious as the used car world is well known as a buyer beware type of place. Unfortunately not everyone is smart enough or clever enough to avoid being taken by private seller, or by a dealer trying to pass off a dog that they themselves got burned on by not being careful about a trade in. Yea it happens a lot and I know that (despite lots of car expertise) from direct personal experience.
In my world, any buyer/seller transaction for value where the seller deliberately misleads is fraud, regardless of whether the buyer is a business (like a car dealership) or a single person. As someone else posted, do unto others.... Hopefully we can leave it at that.

Scott R

Sorry Jabberwock. I appreiciate your comments, so as you said, let's try to leave any potentially fraudulent questions/advice out of this thread, and focus on what the underlying issues might be.

OK, so after I left my battery unplugged for a long while (probably much longer than was necessary), I plugged it back in and the CEL was off, as expected. Surprisingly, though, the VSC lights were still on, which had me worried that there was an actual problem related to that. Why would unplugging the battery clear the CEL but not the VSC lights? In any case, I then used the paperclip jumper trick and successfully cleared those lights.

So now all lights were off and I decided to take it for a quick spin around my neighborhood, to see how long the happiness would last. I drove it for a few miles and then back to my driveway and stopped in front of my garage. And then I *swore* I saw the CEL back on. Oh no. I shut off the car and then plugged the code reader back in, turned on the car, and scanned everything. My iOS app informed me that there were no issues. What? So then I shut off the car, unplugged the reader, and started the car again. The CEL was still off, but now one of the VSC lights was on again. Turned off the car, inserted the paperclip jumper, etc., etc., shut off car, removed clip (might have those last two reversed), and then started the car again and everything looked good.

Now it's possible that I somehow imagined seeing the CEL on again for that brief moment. I say this because I've had my tire pressure light on for a very, very long time, and it's also yellow. But I don't know how I could have all of a sudden, for a brief moment, mistaken that light for the CEL. But then if it was the CEL, I don't think I've ever seen my CEL go on and then back off by itself. Weird.

Scott R

OK, so I'm still a little worried about that ghost CEL light situation, but now I'm also cautiously excited that I may have not only legitimately fixed the evap codes by reconnecting the hose, but that I may have actually fixed the O2 sensor code as well. I could have sworn that someone told me in one of my threads (but it doesn't look like it was this one) that the two codes were unrelated. But I just Googled the two things and came up with multiple articles indicating that a disconnected vacuum hose could indeed cause the O2 sensor code to mistakenly be raised. The O2 sensor code was for the front driver side, which I believe is located in the general area (but on the underside) of where this vacuum hose was, so it makes sense to me (of course, I don't know much about auto repair).

Anyway, if that's the case, then thanks again to everyone here who steered me in the right direction.

Also, now this little factoid could be a good way for me to quiz mechanics I'm thinking of using. If they think there's no way the two could be related, I'll know to bring my business elsewhere.

Jabberwock

If your CEL stays off for more that 30 minutes or so of driving than likely the problem has been corrected. Typically CEL does not flash on temporarily in normal operations except for the initial system and fault lights check at start up.

Prasha

Finally, guess you read my post....

pros call it the 'idiot light'

Scott R

Welp, I went out tonight and within 15 mins of driving, the CEL went on again. Pulled over, popped the hood, and confirmed that the vacuum hoses hadn't come loose. I'll pull the codes tomorrow.

DshngDaryl

One of the reasons we knew to tell you to check the hose is because it is a common problem on the SC. However it is not limited to just that one hose. There are about 6 hoses all in the same area that have been exposed to the same conditions. It is a relatively easy fix and less than $10 if you do it yourself using generic hose. A leak in any of those 6 hoses can cause the CEL.

All you have to do is take one broken hose to an auto part store and ask them for vacuum hose the same size. I would ask for hose that is 6 feet long. In AZ it is 74 cents a foot. Then you will probably need some hose clamps to fit the vacuum hose, one for each side.

You take one of the old hoses off, use it as a measuring stick to cut the new hose to length and then replace it with the new hose. Only do one at a time and you will not get confused where they go.

The slight downside is, if people look at the engine, they can tell that the hose job was not done by Lexus and possibly offer you less. Still, the problem will be permanently fixed and I believe you will get more than with a car with a CEL light on.

Scott R

Thanks for the reply. In my case, the hose had gotten detached but didn't look like it needed to be replaced. Should all of the vacuum hoses look the same and be visible with the hood up? I only saw the two hoses together on the side in the photo. Shortly I'll pop the hood and try to locate all six.

Scott R

OK, so I popped the hood to look for other vacuum hoses and couldn't find any that were easily accessible. I started to make an attempt to remove the engine cover but I didn't have the proper tools, so then I scanned the codes again. The P0135 (O2 sensor Bank 1, Sensor 1) code is what's on. The three evap codes I was getting before are not.

My car was close to empty, and I wondered if that, combined with the hose being detached recently, might be causing any false alarms, so I cleared the code and drove about 5 miles to a Shell station to fill up. After about 4 miles, the CEL went on again. I filled up (can't remember if the octane was 91 or 93 there), cleared the code again, and drove back home. Again, after about 4 miles, the CEL went on again. I cleared it again and parked it in the garage.

So to remind you of some background, the very first time the CEL went on I didn't have my own code reader, so I brought it to a shop. The guy seemed to indicate that the only code(s) he was seeing were for a minor evap leak, so he checked the gas cap, cleared the code(s) and told me to wait to see if it came up again.

The next time the CEL went on (about a week later) I had my code reader and saw the three evap codes (one major) and the P0135 O2 sensor code. I found the detached vacuum hose, reattached it, cleared the codes, and the evap codes have stayed off.

So a couple of questions:
1) It looks like the evap codes were caused by the detached hose and pre-dated (by a week) the O2 sensor code. Is it possible/likely that the detached hose *caused* damage to the O2 sensor? It seems unlikely to me that the O2 sensor was about to fail all on its own within the same week that the hose became detached.

2) Is there any chance that the O2 sensor isn't damaged and that there's just some "bad oxygen" in the system as a result of the detached hose, and that if I keep driving it for a while it will clear itself up and the code will stop firing?