ClubLexus - Lexus Forum Discussion
Page 1 of 2
1
2
Show 40 post(s) from this thread on one page

ClubLexus - Lexus Forum Discussion (https://www.clublexus.com/forums/)
-   RC F (2015-present) (https://www.clublexus.com/forums/rc-f-2015-present-259/)
-   -   2nd to 1st shift (jerk, push etc symptom) (https://www.clublexus.com/forums/rc-f-2015-present/908532-2nd-to-1st-shift-jerk-push-etc-symptom.html)

BlueRCF10 01-09-19 09:46 AM
2nd to 1st shift (jerk, push etc symptom)
 
Hey Guys,

As you might know, Lexus/Toyota has an ECM issue they never seemed to have fix for various makes/models which displays itself in a less than smooth downshift from 2nd to 1st gear. Some people notice it some people don't or some people just accept the car as is as one if it's characteristics. Many Lexus forum members have reached out to SIA Electronics in Illinois to have their ECM fixed and it has worked. I am currently in the process of doing this for my 2008 GS350 as it has this issue. I'm confident that the issue will be resolved and look forward to having this issue fixed.

On the other hand, I noticed my RCF does this as well as I recognize the symptoms from my GS. I contacted SIA and they do not have a fix for this yet for our model yet. I was wondering if anyone else has found any solution to this? Once I take my car out of storage, I'll be re-flashing the computer at the dealer to re-learn my driving styles etc as the car is new to me. But through research, I've read that this does not fix the issue. The car shifts beautifully and gracefully through all the other gears. My warranty is up in June of 2019 and I'll try to somehow get this fixed through the dealer but when I mentioned this to them they sorta acknowledged the issue and said that there isn't a fix.

Love the car but this is my only minor issue with it. I doubt passengers feel this subtle symptom but it personally bugs me.

Let me know your thoughts....

GunnyFitz 01-09-19 10:21 AM
Hmmm, never once thought this was a problem since shifting to 1st gear means you are extremely close to a stopped position. I personally don't use this gear for Engine Braking.

BlueRCF10 01-09-19 10:25 AM
Originally Posted by GunnyFitz (Post 10404655)
Hmmm, never once thought this was a problem since shifting to 1st gear means you are extremely close to a stopped position. I personally don't use this gear for Engine Braking.
You made me doubt myself and it could be from 3rd to 2nd. Regardless it’s there and it’s subtle but bothers me. It should be smooth shifting throughout all the downshifts. It’s bothersome to me just anticipating that little hiccup.

I’m talking about this in full auto mode. No engine braking involved.


lobuxracer 01-09-19 11:44 AM
The GS F does this too. My IS F does not. I just assumed it was a different TCU with "updated" code and it is normal for the GS F to do this.

BlueRCF10 01-09-19 11:54 AM
Originally Posted by lobuxracer (Post 10404739)
The GS F does this too. My IS F does not. I just assumed it was a different TCU with "updated" code and it is normal for the GS F to do this.
Various Lexus models do this. Some do and some don’t. Lexus misdiagnosed many cases and people paid for new trannys and new ECU’s. Ridiculous actually.

To me, I’ll accept it until SIA or another company has a fix. I’ll re-flash it under warranty for now....

finny76 01-09-19 01:13 PM
Originally Posted by lobuxracer (Post 10404739)
The GS F does this too. My IS F does not. I just assumed it was a different TCU with "updated" code and it is normal for the GS F to do this.
I experience rough shifts usually from 2 to 3 on my GSF.

BlueRCF10 01-09-19 01:46 PM
Originally Posted by finny76 (Post 10404810)
I experience rough shifts usually from 2 to 3 on my GSF.
Rough upshift from 2-3? Or downshifts from 3 to 2?

finny76 01-09-19 06:27 PM
Up shifts from 2-3 i.e when I'm in gear two and then it just puts it in 3 with a Jerk.

BlueRCF10 01-09-19 06:33 PM
Originally Posted by finny76 (Post 10405148)
Up shifts from 2-3 i.e when I'm in gear two and then it just puts it in 3 with a Jerk.
That’s different from this cause but Lexus trannys are pretty bulletproof in general.

I’d get a ref-flash and a tranny oil change (Check to see if it’s recommended).

brendanf 01-11-19 03:32 PM
You should never downshift from 2nd to 1st unless you are going incredibly slow AND slowing down.

This is is a normal behaviour even for a manual transmission.

BlueRCF10 01-11-19 03:43 PM
Originally Posted by brendanf (Post 10406972)
You should never downshift from 2nd to 1st unless you are going incredibly slow AND slowing down.

This is is a normal behaviour even for a manual transmission.
As I clarified above, it’s from 3rd to 2nd most likely.

brendanf 01-11-19 04:04 PM
Well that’s a bit different.

The RCF is a bit strange in how it handles the downshifts from one gear to another.

It looks at several things,

1. Is the car up to temperature yet
2. How hard are you braking
3. And, where will the revs land if it rev matches.

Ive found until the car is at operating temp, most of the fun stuff is locked out and it drives in a boring fashion.

Brake pedal pressure seems to be the key in my experience. If I’m braking hard enough then I will get a nice throttle blip and rev match from the ECU even in AUTO.

BlueRCF10 01-11-19 04:47 PM
Originally Posted by brendanf (Post 10407004)
Well that’s a bit different.

The RCF is a bit strange in how it handles the downshifts from one gear to another.

It looks at several things,

1. Is the car up to temperature yet
2. How hard are you braking
3. And, where will the revs land if it rev matches.

Ive found until the car is at operating temp, most of the fun stuff is locked out and it drives in a boring fashion.

Brake pedal pressure seems to be the key in my experience. If I’m braking hard enough then I will get a nice throttle blip and rev match from the ECU even in AUTO.
I agree. This symptom I’m describing usually occurs when the car is fully warmed up.

MrJeager 01-11-19 05:42 PM
Since I drive in manual and sport + all the time - I've memorized the best down shift points for the ECU to perform a "proper" rev match and blip duration:

From 4 -> 3: 90-100 KM /h
From 3 -> 2: 65-70 KM /h
From 2 -> 1: 35-40 KM /h

These downshift points are useful only when the engine oil and coolant are at optimal temp (triangles in the middle). You'll know when the car is ready for a beating once your G-Sensor / Brake and Accel sensors are showing values and aren't grey'ed out under the F menu. The red-line crawling back to 7300 RPM is not a good indicator.

You have to be very very careful shifting from 2 -> 1 at a speed slower than 35 KM/h - the downshift will be rough and the car will jerk unnaturally. Aim to downshift to 1 near 40 KM/h.

As for upshift - as close to red-line / limiter as your heart desires :)

BlueRCF10 01-11-19 05:45 PM
Originally Posted by 3IS350Guy (Post 10407093)
Since I drive in manual and sport + all the time - I've memorized the best down shift points for the ECU to perform a "proper" rev match and blip duration:

From 4 -> 3: 90-100 KM /h
From 3 -> 2: 65-70 KM /h
From 2 -> 1: 35-40 KM /h

These downshift points are useful only when the engine oil and coolant are at optimal temp (triangles in the middle). You'll know when the car is ready for a beating once your G-Sensor / Brake and Accel sensors are showing values and aren't grey'ed out under the F menu. The red-line crawling back to 7300 RPM is not a good indicator.

You have to be very very careful shifting from 2 -> 1 at a speed slower than 35 KM/h - the downshift will be rough and the car will jerk unnaturally. Aim to downshift to 1 near 40 KM/h.

As for upshift - as close to red-line / limiter as your heart desires :)
Useful info for sure! But I’m driving it in auto “normal” mode when this occurs. It’s a know Lexus/Toyota issue and they don’t have a fix for it unfortunately.


All times are GMT -7. The time now is 04:07 AM.
Page 1 of 2
1
2
Show 40 post(s) from this thread on one page


© 2024 MH Sub I, LLC dba Internet Brands