Hesitation problem at various speeds (TSB info post #159)
05-25-18, 09:12 AM
#842
Driver School Candidate
ECU Reset Question???
Has anyone tried to reset their ECU chip themselves? I've heard of the dealer/service department doing it on occasion, but I don't think they like to do it very often. What are the problems with resetting the ECU. I'm thinking my initial learning was mostly done on ECO mode, but now I'm driving more on Normal mode. I'm driving more on Normal Mode because the car seems jerky, rough and hesitate, especially from a stop to go at lower speeds. I'm not totally happy with the car's transmission, even on Normal Mode now. It seems to me that it was driving better when it was new and still learning my driving habits, now I have 6,500 miles. At the 5,000 mile service, I mentioned the hesitation/jerky transmission issues and they told me to try premium gas for a few tanks before I'll notice a difference and explained that especially gas in California is rough due to EPA and State emissions regulations. I did that and only noticed a slight improvement, but sill not satisfactory for me especially considering premium fuel is not indicated or recommended by the manufacturer plus it costs more. I also tried the Amazon Powertune (bought thru eBay), and the jury is still out, but so far I don't think it's really helping much if at all (I've used it for over 100 miles or so as recommended, and tried for comparison to leave in and remove and drive around and don't really think it's doing anything much if at all). I also know and heard about the TSB, but when I asked service department at my 5,000, they said they're not doing it unless they feel the car really needs it, or something like that. I set a separate appointment next week specifically for this issue, so we shall see. But I'm expecting them to test drive and tell me nothing is wrong and this is how it's supposed to be. BTW: I have the AWD RX350 2017 model.
05-25-18, 09:43 AM
#843
Advanced
Has anyone tried to reset their ECU chip themselves? I've heard of the dealer/service department doing it on occasion, but I don't think they like to do it very often. What are the problems with resetting the ECU. I'm thinking my initial learning was mostly done on ECO mode, but now I'm driving more on Normal mode. I'm driving more on Normal Mode because the car seems jerky, rough and hesitate, especially from a stop to go at lower speeds. I'm not totally happy with the car's transmission, even on Normal Mode now. It seems to me that it was driving better when it was new and still learning my driving habits, now I have 6,500 miles. At the 5,000 mile service, I mentioned the hesitation/jerky transmission issues and they told me to try premium gas for a few tanks before I'll notice a difference and explained that especially gas in California is rough due to EPA and State emissions regulations. I did that and only noticed a slight improvement, but sill not satisfactory for me especially considering premium fuel is not indicated or recommended by the manufacturer plus it costs more. I also tried the Amazon Powertune (bought thru eBay), and the jury is still out, but so far I don't think it's really helping much if at all (I've used it for over 100 miles or so as recommended, and tried for comparison to leave in and remove and drive around and don't really think it's doing anything much if at all). I also know and heard about the TSB, but when I asked service department at my 5,000, they said they're not doing it unless they feel the car really needs it, or something like that. I set a separate appointment next week specifically for this issue, so we shall see. But I'm expecting them to test drive and tell me nothing is wrong and this is how it's supposed to be. BTW: I have the AWD RX350 2017 model.
Some disconnect the battery for a couple of minutes to reset it.
05-25-18, 01:37 PM
#844
Has anyone tried to reset their ECU chip themselves? I've heard of the dealer/service department doing it on occasion, but I don't think they like to do it very often. What are the problems with resetting the ECU. I'm thinking my initial learning was mostly done on ECO mode, but now I'm driving more on Normal mode. I'm driving more on Normal Mode because the car seems jerky, rough and hesitate, especially from a stop to go at lower speeds. I'm not totally happy with the car's transmission, even on Normal Mode now. It seems to me that it was driving better when it was new and still learning my driving habits, now I have 6,500 miles. At the 5,000 mile service, I mentioned the hesitation/jerky transmission issues and they told me to try premium gas for a few tanks before I'll notice a difference and explained that especially gas in California is rough due to EPA and State emissions regulations. I did that and only noticed a slight improvement, but sill not satisfactory for me especially considering premium fuel is not indicated or recommended by the manufacturer plus it costs more. I also tried the Amazon Powertune (bought thru eBay), and the jury is still out, but so far I don't think it's really helping much if at all (I've used it for over 100 miles or so as recommended, and tried for comparison to leave in and remove and drive around and don't really think it's doing anything much if at all). I also know and heard about the TSB, but when I asked service department at my 5,000, they said they're not doing it unless they feel the car really needs it, or something like that. I set a separate appointment next week specifically for this issue, so we shall see. But I'm expecting them to test drive and tell me nothing is wrong and this is how it's supposed to be. BTW: I have the AWD RX350 2017 model.
05-25-18, 04:44 PM
#845
Driver School Candidate
I filled my last 3 tanks or so with 91 octane, but like I said maybe a slight improvement is all, if anything. I'm still not happy with the transmission shifting. It seems unpredictable, sometimes feels fines, other times really hesitant,and jerky. Not smooth as butter, like I felt with my previous car, 2005 Toyota 4runner. And like I said, I really didn't notice these issues when the car was new (I guess learning my driving), but now it's more noticeable and unpredictable. That's why I switched gas, after the Lexus dealership told me and eventually tried the powertune device too. Maybe I try to reset the ECU next, not sure. Everything else I love about the car, but this issue is very bothersome. 
05-26-18, 05:37 AM
#846
I filled my last 3 tanks or so with 91 octane, but like I said maybe a slight improvement is all, if anything. I'm still not happy with the transmission shifting. It seems unpredictable, sometimes feels fines, other times really hesitant,and jerky. Not smooth as butter, like I felt with my previous car, 2005 Toyota 4runner. And like I said, I really didn't notice these issues when the car was new (I guess learning my driving), but now it's more noticeable and unpredictable. That's why I switched gas, after the Lexus dealership told me and eventually tried the powertune device too. Maybe I try to reset the ECU next, not sure. Everything else I love about the car, but this issue is very bothersome.
05-26-18, 01:57 PM
#847
2015 has a 6 speed transmission.
05-26-18, 05:57 PM
#848
Has anyone tried to reset their ECU chip themselves? I've heard of the dealer/service department doing it on occasion, but I don't think they like to do it very often. What are the problems with resetting the ECU. I'm thinking my initial learning was mostly done on ECO mode, but now I'm driving more on Normal mode. I'm driving more on Normal Mode because the car seems jerky, rough and hesitate, especially from a stop to go at lower speeds. I'm not totally happy with the car's transmission, even on Normal Mode now. It seems to me that it was driving better when it was new and still learning my driving habits, now I have 6,500 miles. At the 5,000 mile service, I mentioned the hesitation/jerky transmission issues and they told me to try premium gas for a few tanks before I'll notice a difference and explained that especially gas in California is rough due to EPA and State emissions regulations. I did that and only noticed a slight improvement, but sill not satisfactory for me especially considering premium fuel is not indicated or recommended by the manufacturer plus it costs more. I also tried the Amazon Powertune (bought thru eBay), and the jury is still out, but so far I don't think it's really helping much if at all (I've used it for over 100 miles or so as recommended, and tried for comparison to leave in and remove and drive around and don't really think it's doing anything much if at all). I also know and heard about the TSB, but when I asked service department at my 5,000, they said they're not doing it unless they feel the car really needs it, or something like that. I set a separate appointment next week specifically for this issue, so we shall see. But I'm expecting them to test drive and tell me nothing is wrong and this is how it's supposed to be. BTW: I have the AWD RX350 2017 model.
I bought my RX used, 18,000 km on it, an ex-Lexus head office vehicle - it seemed to drive fine around the unfamiliar dealership area but when I took delivery and drove the 1.5 hours home the hesitation started to show. Once in my familiar area it was obvious it had issues, so started trying different octane fuel, driving differently to allow for the unusual gear changes, trying other fuel again, switching to Sport, then Eco, then Normal and for a while it would seem okay but then back to awful. At the 30,000 km service I mentioned the issue, they found nothing wrong but did reset the ECM and wow, a different car, it was obviously better and once back to familiar territory it felt great - mostly. That's when I realised the car has two personas, drive gently and it's fine in Normal mode, want to go faster put it in Sport. The moral of my story is I feel this learning transmission is trying to be too smart - I bought the car used so it was use to another person driving, I started driving it, felt unhappy with it and kept changing fuels and driving techniques which basically kept changing that learning pattern and screwing up the whole process, at the service the ECM was reset and back to standard and has been great since (if I use the appropriate mode for the conditions). Anyway that's my story - maybe the US models have a more fuel efficient mapping as I know economy is a big thing over there, this would mean sooner up-changes then ideal but better headline fuel consumption, and this may mean even more poor driving characteristics compared to ours.
Ask the dealer to reset, I don't know why they wouldn't or don't like to, not going to harm anything or take long.
Also what's interesting is in Australia our manual says to use the mid tier fuel (Premium 95 OCT - AKI 90) which I always do now, whereas in North America the manual says regular (AKI 87).
05-26-18, 08:32 PM
#849
Driver School Candidate
Don't know if you saw my post - I'll repeat it here:-
I bought my RX used, 18,000 km on it, an ex-Lexus head office vehicle - it seemed to drive fine around the unfamiliar dealership area but when I took delivery and drove the 1.5 hours home the hesitation started to show. Once in my familiar area it was obvious it had issues, so started trying different octane fuel, driving differently to allow for the unusual gear changes, trying other fuel again, switching to Sport, then Eco, then Normal and for a while it would seem okay but then back to awful. At the 30,000 km service I mentioned the issue, they found nothing wrong but did reset the ECM and wow, a different car, it was obviously better and once back to familiar territory it felt great - mostly. That's when I realised the car has two personas, drive gently and it's fine in Normal mode, want to go faster put it in Sport. The moral of my story is I feel this learning transmission is trying to be too smart - I bought the car used so it was use to another person driving, I started driving it, felt unhappy with it and kept changing fuels and driving techniques which basically kept changing that learning pattern and screwing up the whole process, at the service the ECM was reset and back to standard and has been great since (if I use the appropriate mode for the conditions). Anyway that's my story - maybe the US models have a more fuel efficient mapping as I know economy is a big thing over there, this would mean sooner up-changes then ideal but better headline fuel consumption, and this may mean even more poor driving characteristics compared to ours.
Ask the dealer to reset, I don't know why they wouldn't or don't like to, not going to harm anything or take long.
Also what's interesting is in Australia our manual says to use the mid tier fuel (Premium 95 OCT - AKI 90) which I always do now, whereas in North America the manual says regular (AKI 87).
I bought my RX used, 18,000 km on it, an ex-Lexus head office vehicle - it seemed to drive fine around the unfamiliar dealership area but when I took delivery and drove the 1.5 hours home the hesitation started to show. Once in my familiar area it was obvious it had issues, so started trying different octane fuel, driving differently to allow for the unusual gear changes, trying other fuel again, switching to Sport, then Eco, then Normal and for a while it would seem okay but then back to awful. At the 30,000 km service I mentioned the issue, they found nothing wrong but did reset the ECM and wow, a different car, it was obviously better and once back to familiar territory it felt great - mostly. That's when I realised the car has two personas, drive gently and it's fine in Normal mode, want to go faster put it in Sport. The moral of my story is I feel this learning transmission is trying to be too smart - I bought the car used so it was use to another person driving, I started driving it, felt unhappy with it and kept changing fuels and driving techniques which basically kept changing that learning pattern and screwing up the whole process, at the service the ECM was reset and back to standard and has been great since (if I use the appropriate mode for the conditions). Anyway that's my story - maybe the US models have a more fuel efficient mapping as I know economy is a big thing over there, this would mean sooner up-changes then ideal but better headline fuel consumption, and this may mean even more poor driving characteristics compared to ours.
Ask the dealer to reset, I don't know why they wouldn't or don't like to, not going to harm anything or take long.
Also what's interesting is in Australia our manual says to use the mid tier fuel (Premium 95 OCT - AKI 90) which I always do now, whereas in North America the manual says regular (AKI 87).
06-13-18, 07:24 PM
#850
Driver School Candidate
Join Date: Jun 2018
Location: MA
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Not good...
Just bought a new RX350 F Sport a few weeks ago. The transmission is just terrible at speeds between 20 and 40 miles an hour. The engine drones constantly, which is most tiresome and unpleasant, especially in a $60K vehicle. The car is slow from the start and at low speeds. I have already taken it back to the dealer, but they said it was normal and there is nothing they can do about it. A mechanic drove it around with me and suggested using premium gas, drive in S or S+ modes and wait for any updates for the 2018 year model. Using premium gas has helped a little, but the car is still not really smooth at all at below 40 mph speeds. In short, I am really disappointed in Lexus and probably will not buy another ever again. With $60K to spend I can definitely do better than this.
06-14-18, 07:10 AM
#851
Just bought a new RX350 F Sport a few weeks ago. The transmission is just terrible at speeds between 20 and 40 miles an hour. The engine drones constantly, which is most tiresome and unpleasant, especially in a $60K vehicle. The car is slow from the start and at low speeds. I have already taken it back to the dealer, but they said it was normal and there is nothing they can do about it. A mechanic drove it around with me and suggested using premium gas, drive in S or S+ modes and wait for any updates for the 2018 year model. Using premium gas has helped a little, but the car is still not really smooth at all at below 40 mph speeds. In short, I am really disappointed in Lexus and probably will not buy another ever again. With $60K to spend I can definitely do better than this.
06-14-18, 09:45 AM
#852
Driver School Candidate
Join Date: Jun 2018
Location: MA
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All I see here is a lot of complaining about the same issue... in any event, I don't think there is any TSB for the 2018 model year yet. I haven't seen it online and my Lexus mechanic has told me so.
06-22-18, 10:36 AM
#854
Just had the dealer reset my ECU and the car now drives much better. Maybe a placebo effect? The RX felt lethargic while taking off from an intersection and pretty much any speed below 40 km/h. That is no longer the case, so I'm quite pleased with the result after the ECU reset.
06-22-18, 05:40 PM
#855
Just had the dealer reset my ECU and the car now drives much better. Maybe a placebo effect? The RX felt lethargic while taking off from an intersection and pretty much any speed below 40 km/h. That is no longer the case, so I'm quite pleased with the result after the ECU reset.
Do more then two people regularly drive the vehicle?