05RollaXRS

Hello,

I just recently purchased a meticulously maintained 2017 Lexus RX350 F-Sport AWD package 3. It looks, feels and drives like a brand new car. It is a single-owner car that was owned by a senior couple. Initially, I had thought the tires were cr*p (Goodyear Assurance ComfortDrive). I raised the tire pressure up to 38 psi front and 40 psi rear, which made things a little better, but still SPORT+ mode was not tightening up the steering and stiffening the dampers at least to the point that it was disorienting. I came from a 2014 Lexus RX450h with Michelin Latitude UHP tires so I was expecting this new one to be firmer and sportier.

Anyway, today I did an experiment where I used the custom mode. In the custom mode, I set the powertrain to 'POWER' and then the chassis to 'SPORT' and then the climate control to 'NORMAL'. My theory proved correct as when I selected the CUSTOM mode, it did the magic. The steering became heavy and stiff. The dampers and the body control really tightened up. I had a lot more confidence under sudden maneuvers.

So my question is, what might have been done by the previous owners to the SPORT+ mode? Is it possible to alter the SPORT+ mode by picking individually the settings like in the case of CUSTOM mode? There is definitely a big difference between my CUSTOM mode with everything dialed up and the SPORT+ mode where SPORT+ feels floaty, steering over boosted/loose with a dead spot and not confidence inspiring at all (experienced ploughing/understeer in turns a few times due to the slow steering response) while the CUSTOM mode has exactly what I would expect SPORT+ mode to be like. Steering feels heavy, suspension feels firm and no ploughing in turns and the steering has the typical progressive heavy build-up in turns directly proportional with the amount of lock. All of these things I would expect to be in SPORT+ mode, but it is not. CUSTOM mode gives me all of that. I am thinking about resetting the ECU by disconnecting the negative terminal for 30 minutes unless someone has a configuration that might have been altered in my car.

I found some old threads of people with 2017 RX350 F-Sport doing update on the ECU for a TSB (hesitation of the transmission) and for them, the SPORT+ mode vanished entirely until they did a reset on the ECU. For me, the SPORT+ mode is there, but it feels more or less the same as the NORMAL mode. Soft suspension, loose steering and slow throttle response. CUSTOM mode behaves the way I would expect SPORT+ mode to behave.

Any inputs or thoughts would be much appreciated.


Update: I solved my issue myself by just resetting the ECU a couple of times. It ended up making SPORT+ feel as it should in terms of steering feel/heft/quickness as well as suspension, throttle response and transmission shifts. I did a short test drive toggling several times between my CONFIGURE mode and the SPORT+ mode. I could not detect any difference anymore between the two, which leads me to believe resetting the ECU fixed the issue. The steering speed and floatiness is gone in SPORT+, which is one of the main reason why I only drive in SPORT+ mode.

Wondering unbeknownst to how many people who might be experiencing the same issue while using SPORT+ mode? The difference is stark between everything dialed up to the max and the normal configuration.

p.s. Goodyear Assurance ComfortDrive are still garbage tires. Very quiet and very comfortable, but way too soft with tendencies to wander and definitely don't feel like low rolling resistance tires that Michelin makes that roll so effortlessly. I will replace them, but at least for now I have solved the major issue.

eddie420

Interesting observations. I will try this out later today and report back.

05RollaXRS

Yeah, it is really odd since it is my third Lexus with SPORT+ mode and never seen this happen before where SPORT+ mode does not make a difference compared to NORMAL mode. You can feel immediately in the steering while in this case, Even my previous RX450h had a SPORT mode where you can feel the throttle and steering change immediately (had no AVS). In this case, the steering remains floaty, overboosted in SPORT+ and with no resistance even lock to lock it turns easily to full lock. Hopefully, battery reset will fix it. For now, I am using CUSTOM mode to get around the floatiness and softness.

ArmdUPSdrv

Hey 05RollaXRS, you need to delete some pm’s. The site says your maxed out and cannot receive any more. 😉

eddie420

I tried swapping between ECO and Sports+ modes at both low speeds and highway speeds, and I could not feel any difference in the steering (the throttle definitely changed). I had to go into Drive Customization and change the default which was set to "Normal". Not sure what to make of it. I have a 2017 RX350 F-Sport as well.

05RollaXRS

@eddie420
Yes, looks like you are having the same issue as me. As I stated in my original post, go into custom mode and select 'POWER' in the drop down for powertrain and 'SPORT' for chassis. The third field is the drop down for climate and leave that in 'NORMAL'. Once you have saved it, push the dial down and you will see CUSTOMIZE appear in the center gauge. If you are facing the same issue as I am then you will feel a very drastic difference between CUSTOMIZE mode and even SPORT+ where CUSTOMIZE is way more aggressive than SPORT+. Try toggling between SPORT+ and CUSTOMIZE mode. You will see the steering gets a lot heavier and responsive in CUSTOMIZE when it feels loose, overboosted/floaty and slow in SPORT+ mode. Clearly, SPORT+ is supposed to behave how it does in CUSTOMIZE mode with all selections in aggressive settings, but the SPORT+ feels exactly the same as NORMAL mode in my case. When you read the manual book, it states that the steering, throttle response, suspension and transmission shifts are all supposed to get aggressive in SPORT+ mode for sporty driving.

05RollaXRS

Update: I solved my issue myself by just resetting the ECU a couple of times. It ended up making SPORT+ feel as it should in terms of steering feel/heft/quickness as well as suspension, throttle response and transmission shifts. I did a short test drive toggling several times between my CUSTOM mode and the SPORT+ mode. I could not detect any difference anymore between the two, which leads me to believe resetting the ECU fixed the issue. The steering speed and floatiness is gone in SPORT+, which is one of the main reason why I only drive in SPORT+ mode.

Wondering unbeknownst to how many people who might be experiencing the same issue while using SPORT+ mode? The difference is stark between everything dialed up to the max and the normal configuration.

p.s. Goodyear Assurance ComfortDrive are still garbage tires. Very quiet and very comfortable, but way too soft with tendencies to wander and definitely don't feel like low rolling resistance tires that Michelin makes that roll so effortlessly. I will replace them, but at least for now I have solved the major issue.

eddie420

My understanding is the ECU(s) firmware learns your driving habits and modifies set points over time, which is why resetting the ECU fixes many 'issues'. Unfortunately, I was not aware that driving modes were also prone to this learning behavior. Somewhat defeats the purpose of calling something "SPORT+" if it's not going to truly go into that mode. Thanks for keeping us updated.

05RollaXRS

@eddie420 Yes, correct. It is always adjusting, which is different than how it is in my other car with AVS, which is a 2019 IS350 F-Sport where it is more consistently in terms of damping forces. In the RX, whether I use CUSTOM mode or SPORT+, it seems to always be varying probably like you said, different parameters including the driving patterns and the surface condition etc. At least, now I have both SPORT+ and CUSTOM mode behaving the same way. Anyway, it is a minor quibble as I am sure once I get much better tires, it will become less of an issue.