No way would I let them disassemble anything until the fault is persistent. It could be mechanical, it could be electronic, it may be a simple wiring problem from an intermittent connection.

No, don't insist they do anything until the fault is persistent. You will only be without your car for a long time while they try to replicate it, and when they fail to replicate it, you'll just be losing time with your car. Be patient, it's far better to have a hard break than one of these kinds of faults.

 

I guess one of my biggest fears is that the problem doesn't return until the car is out of warranty. And then it's not only time away from my car but expense. Do you think there is any more diagnostic work to be done to further narrow down the problem?

 

If they've read the stored codes, there really isn't anything else to do but note it in the service records. Don't forget, if you have a problem with this part of the car, and the service they've done so far is documented, you'll have no problem getting Lexus to take responsibility for solving your issue.

It's very unlikely you'll have to have out of warranty repairs. If the problem is going to happen again, it will likely be fairly soon in a relative sense. Some things to keep in mind - you need to replicate the conditions that caused your problem. For instance, I had a problem with my Supra that only showed up when the car sat out in the cold (below 40F) overnight. Any other time, it started and ran fine, but when it fully cold soaked, it ran like crap for about 10 minutes, then once it warmed up it ran fine for the rest of the day. It took some time and effort to troubleshoot, but it ended up being a bad connection in one of the ECM connectors (I won't bore you with the details of hours of troubleshooting and attempting to replicate the problem, but I literally spent 25 hours troubleshooting.)

So, to help understand what causes the problem, you need to immediately note the environmental conditions when the problem occurs, and anything usual or unusual you did when it happened. It helps troubleshooting immensely. Otherwise, you're playing 50 questions with the service advisor trying to divine exactly what circumstances cause the fault to occur.

 

Makes sense. If for some reason the same code comes up again, yet it is no longer there when I go in for service, is there really ever anything that can be done? It almost seems as if the ONLY way they can further narrow don the problem is to see the code on when I bring it in the dealership, and even THEN, what can they do without taking apart the host of parts, referred to in the code?

Also, if the problem subsides outside of warranty again, and persists, do you think they may cover, since it initially happened early on?

Thx again!

 

The codes are stored in memory. They don't just disappear unless you either disconnect the battery (clears some codes) or reset the ECM with a scan tool (clears all codes and restores default parameters.) So if this happens again, they'll see the old code and potentially any new codes to help them understand what is going on.

They'll spend a lot of time tracking down the root cause before they spend any time disassembling bits because warranty fixes things broken. The service advisor needs to have a clear picture of what is wrong and what it will take to fix it before the warranty repair work will be approved by Lexus. Lexus actually pays the dealership for warranty work (at a slightly reduced hourly rate), so the dealership has to make a fair and reasonable effort to troubleshoot the problem. If they troubleshoot and find nothing, but your symptoms persist, then they'll call in a regional service advisor who will determine what steps they take next, and typically has a "super tech" who is assigned to solve the issue if no one else is successful in fixing it.

In your case, you're doing everything right. You have it documented, you remember the DTC, and you'll know to take the car in for service should you see the warning lights again to further document (and most likely solve) your problem.

It's never prudent to just start disassembling something if it is working, even if it's spitting out codes. There's a process they need to use to isolate the issue, find likely root causes, and use a process of elimination to find the exact cause. Many times when you just start disassembling, you find nothing unusual, and you end up putting everything back together only to find there is still something wrong, and worse yet, you really don't know where to start. I've even seen guys tearing their hair out because they didn't find anything, they put it all back together, and there were MORE problems than when they started...

Be patient. Let it fail again (if it will), and have it fixed when its really broken.

 

Lexus kept my car for a week to fix the problem.(as I do live about 2 hours away) From what my mechanic at the dealership told me, he had to e-mail pics to Japan for them to configure and arrange the adjusters. I never smelled gas and the car never performed bad either. I know he said to NEVER ad any addatives to your gas or oil! The mechanic did ask me if I left my car running at a standstill for long periods of time? what this has to do with I don't know; all I do know is he got it fixed sat me down on a Sat. which they are usually closed and showed me the pictures on his computer of what was done. I don't know a whole lot about the direct injection IS yet so alot of what he was saying was over my head? The car only had about 6,000 miles on it at that time and now I have 24,000+. I have had NO problems since. The most impressive thing is I did not buy my car from Lexus of Memphis even though it was closer to where i live, I bought it in Nashville TN and when I started having this problem they gave me a 2006 LOADED GS300 to drive for a week. They treat people there with the upmost respect! I will buy an IS350 from them in October 07 and give this 250 to my step daughter taht will be turning 16 as it did receive better than 5 star crash test! (Per Austraillian crash teat results)
Hope you get the problem resolved. I guess I could scan the work report that tells exactly what was done and send it if you would like.
-todd

 

Thx again for the info. FYI, a service tech. just told me it's something Lexus is working on, but invlolves an adjustment which would impact emissions, so they've gotta get approval from the government and that obviously takes a while. So I guess I'll just ride it out. Odd though, I've not heard of ANYONE with a 350 with a similar complaint.