franklexus

I've been driving my LS for around 9 months now. I noticed the car jerks / lurches quite abruptly forward when I take my foot off the brakes slowly, and also when I brake slowly (it doesn't seem to engage properly). I don't remember experiencing this in my early days with the car. Wondering if anyone has the same experience? Thanks!

Problem solved: There is a TSB for this issue which reprograms the ECM: https://www.clublexus.com/forums/ls-...ift-delay.html

shinonclub

Which version of the LS 500 do you have? My LS500 regular version does not seem to have any problems with the break system.

seanspeng

franklexus

Thanks for the replies! I have the regular LS 500. I will bring it in to have them take a look at it.

dsc07

I don't think what you're feeling is a break issue, it is a transmission issue. Gears 1-4 are not configured correctly. The lurching is most pronounced during gradual deceleration/acceleration.

AustinHusk

Sounds like the same issue I have with my 2015 F Sport!

franklexus

I've observed it a bit more and you're right! The lurch is very pronounced and definitely un-Lexus like!

seanspeng

dsc07

Horsepucky!

seanspeng

kghoshal

Folks... this may help you. I had to literally get into a "science project" mode to get to the bottom of this issue. You may have caught one of my narratives on this exact topic under a different thread. Since then a fair amount of water has flown under the proverbial bridge in the past 3 weeks. Let me explain the lengths I went to... if it helps some of you fellow afflicted ones.

I received delivery of my LS500 back in Feb (one of the very first lots to arrive in the US). Being relatively cold that time of the year in Dallas, I attributed the "lurching" to cold-starts of the engine. Which turned out to be somewhat true... it'd lurch at EVERY cold start - and that could happen (in the cool season) for anything beyond a 6 hour stop for my car. Annoying at first, it started to become a nuisance after 3 months of driving... as it started to do the same after every gear shift from reverse to drive as well. The dealer - to be fair at that point in time - had not received such complaints from Dallas area owners/drivers of 5LS. They asked me to monitor (and I've been a client of this dealer for 20 years through 6 LSs in a series) the performance and report back, given that they no feedback from corporate Lexus re this issue at that time.

I just couldn't take it any more 3 weeks ago - after having driven for 8 months and approx 3K miles (yes, I tend to put on very few miles on my car). But it was long enough and enough miles for them to run "forensics" on the issue. After the last straw was had by me, I took it to the dealer and had them run all kinds of tests. They kept the car for observation and tests for two days, dedicated the head tech of the dealer, who in turn called upon Lexus corporate head techs.for answers (and YES, he was able to simulate the "lurch"). After two days, the dealership called and informed "unfortunately there is no known solution/fix for this issue". Apparently it is a firmware issue and Tokyo is aware of this (due to numerous inputs from the first-batch of buyers by now). There'll be a wholesale firmware patch on the 2018 5LS models once it's completed.

This is where I deviate from the usual LS story. Given the longevity of my relationship as a client to this dealer, they offered to "buy the car back" and fit me with a new LS. Which I proceeded to do two weeks ago. It's still a 2018 LS500 - but from the second batch of production. And in this case I upgraded from the base model to the model with enhanced package (the one with mark Levinson audio system). As of now, this is car has about 400 miles on it... have not experienced the acute lurch that I did with the previous one (fingers firmly crossed of course... it's only been 2 weeks) - don't know if the "upgraded" car has anything to do with transmission/firmware issues (I thought the upgrade was purely on the cosmetic side of things. However, if this helps any of the fellow afflicted ones... for whatever it's worth :-)

seanspeng

franklexus

Thanks to all for sharing, much appreciated! Mine was the 1st batch too (got it in February). I've been driving my car around in Comfort mode ever since I got it. The lurch is more pronounced in that mode (I think the car somehow adapted to my style of driving). When I switched it to Normal mode recently, the lurch is much reduced. So I wonder if it is an issue of the transmission "adapting" incorrectly to the driving style over time... I've not had time to bring it in for the service. Perhaps those with the lurch can try switching to Comfort and see what happens.

kghoshal

Many thanks for this tip. Actually hadn't thought of that angle. Am surprised the tech didn't suggest it either - unless they were able to simulate the jerky start-stop in all modes. I waiting to see if my new one start doing the same (currently driving in "comfort" mode).

franklexus

Problem solved! Please see this thread: https://www.clublexus.com/forums/ls-...ift-delay.html