RX - 4th Gen (2016-2022) Discussion topics related to the 2016 and up RX350 and RX450h models

Hesitation problem at various speeds (TSB info post #159)

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Old 07-14-20 | 03:17 PM
  #1411  
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Originally Posted by Onion
Did it end up getting resolved? Which dealer did you take it to? My warranty is coming up (79000km now and expires at October), gonna try my luck at the nearest dealership first to see if anything can be done
Doesn't the TSB fall under the powertrain warranty since it affects the transmission? In that case, you're looking at 72 months or 110,000km from the in-service date, whichever comes first.
Old 07-23-20 | 09:01 PM
  #1412  
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Received a Limited Service Campaign in Canada. It is L48. It will update the ECM again and I am not sure if the update will affect this issue.
Old 07-24-20 | 06:35 AM
  #1413  
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Originally Posted by Onion
Did it end up getting resolved? Which dealer did you take it to? My warranty is coming up (79000km now and expires at October), gonna try my luck at the nearest dealership first to see if anything can be done
I had Erin Park Lexus do it, did it improve anything? Maybe it's a little better in normal mode but it's still not smooth as it should be.

I'm not really sure why they made the transmission behave this way on a premium car. It's the only thing I don't like about this car, the off the line slow take off. Our 2nd get RX has a much smoother, and predictable, low speed take off.
Old 07-24-20 | 07:15 AM
  #1414  
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Originally Posted by mrmonster
I had Erin Park Lexus do it, did it improve anything? Maybe it's a little better in normal mode but it's still not smooth as it should be.

I'm not really sure why they made the transmission behave this way on a premium car. It's the only thing I don't like about this car, the off the line slow take off. Our 2nd get RX has a much smoother, and predictable, low speed take off.
I took my 2016 RX350 into the closest dealership two weeks ago because I couldn't stand the shifting from a dead stop trying to pull out onto a busy road. Long, almost slipping shift and than a jolt into the next gear. I had the TSB applied back in November but I really couldn't tell if it improved shifting or not. This time the service rep told me they reset the ECM which he said hadn't been done the first time.
It made a huge difference and it shifts way more smoothly now. I don't know why that reset was not done the first time.
Old 07-24-20 | 07:28 AM
  #1415  
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Originally Posted by Eric0201
Received a Limited Service Campaign in Canada. It is L48. It will update the ECM again and I am not sure if the update will affect this issue.
I checked mine and its show L43 for a 2019. I had one done last Fall, so I am wondering if this is the same or this is a newer one.
Old 07-24-20 | 02:40 PM
  #1416  
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Originally Posted by 1halifax
I checked mine and its show L43 for a 2019. I had one done last Fall, so I am wondering if this is the same or this is a newer one.
I am not sure. Because other people get L43 letter and include L48 in the letter. You can check this https://www.clublexus.com/forums/rx-...reprogram.html
Old 07-24-20 | 06:12 PM
  #1417  
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Originally Posted by mrmonster
I'm not really sure why they made the transmission behave this way on a premium car. It's the only thing I don't like about this car, the off the line slow take off. Our 2nd get RX has a much smoother, and predictable, low speed take off.
Fuel economy, that why, transmission shifts up too soon than as you give it more throttle to compensate she downshifts. How bad it is depends on topography and driving style; I can drive around my town (30,000 people), which is mostly flat, with small throttle openings and she's as smooth as silk, doesn't change up as soon and the changes are always smooth. When I drive in a big metro area where there's more pace needed and/or more hills she's a pain. That's when I put it in Sport mode and it's far, far better.
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Old 07-24-20 | 06:15 PM
  #1418  
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Originally Posted by Cropdustef
This time the service rep told me they reset the ECM which he said hadn't been done the first time.
It made a huge difference and it shifts way more smoothly now. I don't know why that reset was not done the first time.
When they download the new software the last part of the procedure is to reset the ECM, it appears from what I've read on here that's the part many dealers don't do and hence you are still riding with the old software. Glad she's better now.
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Old 07-31-20 | 10:33 AM
  #1419  
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Three days ago I filled my 2020 RX350 with premium (91 octane) gas. I have about 2500 miles on the vehicle and have used only regular (87 octane) fuel to this point. There is a HUGE improvement in the smoothness and general responsiveness of the engine. I had tried using sport mode to improve the sluggishness, which helped somewhat. But now, I am delighted that by changing to premium I can run in normal mode and it’s like a different vehicle. I highly recommend that anyone having this issue should try this simple solution - it may be a few more cents at the pump, but it’s definitely worth it.
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Old 08-04-20 | 08:30 AM
  #1420  
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Smile Hesitation issue totally fixed ....

My 2018 RX350 with 18,000 miles was experiencing really bad hesitations and surge. It got worse and worse as the vehicle got older and more miles. The local Lexus dealer just replaced the defective fuel pump (factory recall) a week ago and it was like magic. The hesitation and surge totally disappeared. Let's hope there's no more problem.
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Old 08-04-20 | 10:20 PM
  #1421  
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Originally Posted by YWW
My 2018 RX350 with 18,000 miles was experiencing really bad hesitations and surge. It got worse and worse as the vehicle got older and more miles. The local Lexus dealer just replaced the defective fuel pump (factory recall) a week ago and it was like magic. The hesitation and surge totally disappeared. Let's hope there's no more problem.
that's interesting! I have a 2017 model with 21k miles. I get the hesitation quite a lot driving in NYC. Bummer though because my car is not listed for the fuel pump recall .. do we know if the list of cars for the recall are finalized or if more cars will be selected in the near future?
Old 08-05-20 | 04:06 AM
  #1422  
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My 2019 had it where if I was cruising and then gun it the suv would stop and then explode. I did the transmission tsb and i haven’t noticed it again.
Old 08-15-20 | 04:26 AM
  #1423  
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My 2018 RX 350 has had this hesitation basically since I got it. I was very close to selling or trading and took it in for the fuel pump recall as a last ditch effort to be sure it wasnt fixable. I have had the dealership reset the ECU before and had done all previous recalls.

They did the fuel pump recall and reset the ECU and it drives like a normal car. FINALLY! At least for one day. I will keep driving it but maybe it was the fuel pump issue that was recalled?

It is like having a new car.
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Old 08-15-20 | 05:45 AM
  #1424  
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Originally Posted by kwijyboy
My 2018 RX 350 has had this hesitation basically since I got it. I was very close to selling or trading and took it in for the fuel pump recall as a last ditch effort to be sure it wasnt fixable. I have had the dealership reset the ECU before and had done all previous recalls.

They did the fuel pump recall and reset the ECU and it drives like a normal car. FINALLY! At least for one day. I will keep driving it but maybe it was the fuel pump issue that was recalled?

It is like having a new car.
Have you had the TSB for the hesitation done, or did they actually do that as well with the last service?
Old 08-15-20 | 06:28 AM
  #1425  
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I brought the TSB for the hard upshift and downshift and they said that was already. done. I am not sure which TSB you are referring to if it is a different one. The hesitation one was the ECU reset if I am not mistaken.

Edited.

I had this done August 2019 KLA - REPROGRAM THE ENGINE ECU ~|~KLA - REPROGRAM THE ENGINE ECU ~|~KLA ~|~9806 COMPLETED KLA KLA001 .7 LBR

August 2020 brought it in for this one VEHICLE BUCKING ON 1 - 2 AND/OR 2 - 3 UPSHIFTS AND SURGE BETWEEN 0 - 46 MPH. TSB L-SB-0032-19. This one was not done as they said the TCM had already been updated to the latest version and health check was normal.
August 2020. 20LA01 - REPLACE LOW-PRESSURE FP (RX WITH MANUAL RR SEAT) was performed. This was a recall.
August 2020. 20LC03 - REPROGRAM ENGINE CONTROL MODULE was performed.

I dont have any more specific information than that.

Last edited by kwijyboy; 08-15-20 at 07:42 AM. Reason: Updated records



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