Reset Flex Fuel Alcohol/Ethanol Percentage Level with Bidirectional Scan Tool

Recently picked up a 2017 FF Sequoia and didn't investigate this before. Now that I am looking the alcohol % is showing 75% and a long term fuel trim of -20%. No physical signs of issues though and the fuel economy actually seems better than it should be ~18.5, which shouldn't be the case right?
Should I get a tool and reset it anyway?

 

If it were my truck, yes.

When the alcohol percentage is that high, the fuel pump is working harder in flex fuel mode.

 

Okay. I'll order one today.

Any explanation for increased fuel economy? From what I read it should be the opposite?

 

I’d leave it alone. The fuel pump isn’t working any harder. All that’s happening is the computer has closed a valve and so now the pump is sending the full 60psi to the engine instead of bleeding off some pressure and only sending 43psi to the engine. No way I’d risk losing 18mpg. My truck was reading 85% when I scanned it but I had zero issues for three years. Now I did clear mine but noticed zero difference after doing so. If I had to do it all over again, I’d leave it alone.

 

Little confused with everything I've read. The ECM should be sending more fuel volume when it thinks its running e85 to compensate for energy density, but then the long term trim is reducing that number because it thinks it's running rich for e85. So is it basically running near normal anyways?

 

Thank you for the post... I'm considering the same purchase. I have the 2016 4x4TRD Pro 38 gal tank as well, and I'm on the hunt for a way to improve my fuel efficiency. Has doing the fuel density reset helped yours?

 

It will only help if the sensors are not reading correctly.

Tundra and fuel efficiency do not go together.... if you are really concerned about fuel consumption, really look if a truck fits your needs. Must folks using their truck as a truck daily are probably 12-15 mpg depending on load, set up, and traffic patterns

 

I got 8.7mpg towing the side by side up to T2S - honestly I was expecting worse.

 

Well... towing was not addressed in my estimate

 

Absolutely - just hammering home these motors don't sip they chug.

 

Just like the owners

 

Well. @EmergencyMaximum is just going to be appalled by this. He easily could've hit somewhere in the 18mpg range with no ac. Maybe even more.

 

well, I’m not even getting the 12-15 so I feel like something is off.
And Btw, I sat myself down and had the “gas mileage talk” with myself and decided this was a “good with the bad” love affair HOWEVER, this doesn’t mean I won’t push my beast to do her best!

 

Happy Friday y’all!

 

It helped for a while, but my fuel pump was on it's last leg and became a no start issue again, so I ended up replacing the fuel pump myself with a Delphi unit....the Denso through the dealers are on severe backorder, and I was able to get the Delphi through Rock Auto. It wasn't the easiest job to do, but it's running in tip top shape now. The fuel mileage has increased ever so slightly since the fuel/alcohol density reset and new pump. Went from 13-13.5 to about 15-15.5 mpg.