LexusRCF15

The last couple times I've brought my car in for complimentary services, I've asked the service advisors about the transmission (i.e. shifting too early out of gears, lagging etc.) while in Auto in most modes and each time they've told me not to be surprised if Lexus issues an update to resolve this issue. At this point they'really still producing a car with the same annoying habits, what do you think are the odds of Lexus stepping up and correcting the problem? I I drive most days in Sports S+ to avoid some of the issues, but the amplified engine noise gets old and so too does manual mode. I've heard the tcu is complex, and difficult to alter but no one in the aftermarket seems to be interested in resolving this problem either? It's just so frustrating having an awkward slush box behind an awesome motor!

mjeds

yes there is.

it isn't the transmission, it is the fuel pump issue. the update that corrects the low voltage issue that results in the fuel pump noise and loss of power, lag shifting etc, was issued several months ago, and it fixes everything you are complaining about.

thread about it is here:

https://www.clublexus.com/forums/rc-...u-flashed.html


The Service Bulletin entitled 'Abnormal Noise from Low Pressure Fuel Pump 'from the QA Powertrain Departmentpublication_Number: 'L-SB-0031-16'.
Vehicle Applicability: ''15-'16 RC F, 16' GS F'.
T3_ID: '16-TMS-0039-L'.update takes about 30-35 minutes. it will increase the idle speed"


make sure you tell the service advisor that you hear a high pitched whine from the rear seat area when the car is warm after long drives 100+ miles or spirited driving, as most dealerships will not apply this LSB unless you are experiencing the fuel pump noise described in the LSB.

This is what I told my dealer and done and done, flash applied and lagging and hesitation gone.

lexusrus

Yes, STICK 100% to the noise issue and NOTHING ELSE. Otherwise you will either confuse the dealer or give them reasons to NOT DO THE REFLASH bc the reflash addresses ONLY the noise associated with the fuel pump. AND tell them it occurred during your 6+ hours of highway driving. I doubt the dealer will want to go have someone drive your RCF for 6+ hours in an attempt to duplicate the noise.

RC-F Fuel Pump

• #421
  
  lexusrus , 09-06-16 11:52 PM
  
  Above is a repeat of the TSB .
  Credit goes to post #350 above. Please see above.
  
  Evidently the GS-F IS AFFLICTED with this also

shadow1118

@op, apparently you need to get the ECU updated.

LexusRCF15

I did bring the car in for the fuel pump TSB and they put me through hell convincing them to do the reflash. They supposedly did if but the car still responds excatly the same, which leads me to believe they didn't actually do anything. Even if the lag issue is resolved the car will still immediately shift through the lower gears and cruise around city streets in 6th gear, with exception to Sport s+. Sport s+ sits around 3rd or 4th gear around town but almost instantly jumps out of 1st or 2nd unless under heavy acceleration (which is no fun).

lexusrus

I wonder what exactly does your paperwork say?

ISFPOWER

iTrader: (20)

thanks Lexusrus, ill be faxing this to my dealer about 75 miles away before i attempt to even drive down there to have it down. they are the worst lexus dealer to work with which every lexus dealer has always treated me very well. let's see what they do this time.

mjeds

I'm wondering if it was actually done, because myself and dozens of other members have had it done and you can immediately tell the difference.

lexusrus

You WILL NOTICE the higher idle rpms (just a little bit ).

YOU WILL ALSO NOTICE MPG drop a little bit. In eco mode from 29ish to like 26ish. Similar small drops in MPG in other driving modes.

RYLITT

I will have to get this checked out by Lexus too. Has anyone noticed in manual mode it not shifting up properly? I've noticed a few times trying to shift from 2nd or third and it staying in gear until redline and bouncing. Not sure what the deal is here..

mjeds

I beg to differ on your second point.

I don't think the drop in MPG is related to the flash, more likely related to the lack of hesitation resulting in a heavier foot.

My overall average has not changed. I use ECO in stop and go traffic, normal on the highway and Sport+ for a 6 mile stretch of twisty back road every day.. my drive goes like this.. 2 miles to the freeway (ECO), 10 miles on freeway to take daughter to school (Normal), 2 miles back to freeway (ECO), 21 miles freeway toward work (Normal), 6 miles up a 6% grade back twisty road in Sport+ plus manual. 1 mile on side street to office.

I do that drive every day and my MPG has been a solid and consistent 22.3 for 14 months, while the dash mpg meter does fluctuate, I record a hand calculation at every refill and nothing has changed.

rjmalm

I have the same experience with MPG after I got the flash update 4 months ago. You can immediately tell the response difference and it's addicting.
As a result of my heavier foot having so much fun, my MPG did drop for daily driving around town due to more aggressive takeaway from stops. (average like 15-16)
Just as a test, I switched ECO and use a light foot for a few days, I can get back to 22 or 23 driving the same flat in town trips with a few stops, which was no change in MPG that I was getting from before the update.
I really don't have a daily long distance test equal number and length of stops. I can range from 21 to 29 depending on the traffic lights and slope of the roads.
mjeds once posted detailed MPG testing for those interested and I would trust his assessment. His thread "RCF average mpg my long term testing"
https://www.clublexus.com/forums/rc-...ml#post9475613

So I just forget the light foot and let it go and have fun....

lexusrus

You are absolutely right about the heavier foot!!!

It is just too hard to resist!!!!

My MPG numbers are from the dash read out.

mjeds

yeah the dash readout fluctuates, especially if you do the "update" in the trip screen which doesn't reset, but restarts the calculation.

but I get a solid 335 - 345 miles per tank when the light comes on, and it typically takes between 14.8 and 15.2 gallons.. Yes I am OCD about recording my mpg's a habit I learned from my father and mother during the gas shortage in the 1970s.

The overall mpg performance of the car really impresses me, considering every vehicle I have had before this averaged between 12 and 15 mpg. But that is not without my changing up the modes as I drive.. if I leave it in Normal all the time (which I have done to see the difference) it drops to 18-19mpg, so the changing of ECO in stop and go traffic and light to light driving makes a big difference. I suspect if I kept my foot out of it and left it in normal on that 6 mile stretch I have every morning I would see closer to 25mpg..

lexusrus

I'm gonna try real hard to leave it in ECO and drive my 65 miles round trip each day for the next few days in open country highways with small hills and see what my mpg looks like.

I'm also impressed by the RCF's MPG. My old SLK55 AMG with NA 5.5 Liter V8 only gets 18mpg at best on the same above highway drive.