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Discussion Starter · #1 ·
I have a 2015 pro FF SC(85,000 miles) it’s ran fine for 60,000 miles supercharged with the unichip.
The last 15,000 miles the alcohol sensor has been reading high and it’s sometimes is hard to start when it’s cooler outside and busts up at wot. Is there anyway to clear the alcohol % so it will run ok?
 

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Discussion Starter · #2 ·
I spoke with a friend who is a mechanic for Toyota who said there is a update for the ecm just for this and it’s free. They actually update it and drain 4 gallons of gas and add it back to make sure the computer is reading it after the reset.
I’ll let y’all know if this works. Should have it in by next week.
 

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I spoke with a friend who is a mechanic for Toyota who said there is a update for the ecm just for this and it’s free. They actually update it and drain 4 gallons of gas and add it back to make sure the computer is reading it after the reset.
I’ll let y’all know if this works. Should have it in by next week.
See if you can get the update number, or TSB, as I have searched, but not found the update. Might be different for my 17.
 

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There isn't an alcohol sensor on the Tundra FFVs. The system calculates the alcohol percentage based on an algorithm and how the truck runs/reacts on the fuel via O2 sensors and etc.

The last update I remember mentioned was in the 14 model year. I don't think I've heard of a 15 plus being affected. My 14 FFV hasn't had any issues thank the Lord.

By the way.... how you liking the SC and the UNI?

You can reset the value with tech stream but I personally its hard for me to trust the hacked versions out there.
 

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Discussion Starter · #6 ·
Thanks for the info. I’ve had good luck with the unichip so far. The wot shift hesitation is still there but other than that it’s ok. I would like to get a better tune if there is one that actually works on a FF.
I’ll post everything that Toyota does and was told it’s free so we will see.
 

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Discussion Starter · #7 ·
Thanks for the info. I’ve had good luck with the unichip so far. The wot shift hesitation is still there but other than that it’s ok. I would like to get a better tune if there is one that actually works on a FF.
I have a question about resetting with the tech stream. Will the truck run ok after you reset it for awhile?
I’ll post everything that Toyota does and was told it’s free so we will see.
 

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There isn't an alcohol sensor on the Tundra FFVs. The system calculates the alcohol percentage based on an algorithm and how the truck runs/reacts on the fuel via O2 sensors and etc.

The last update I remember mentioned was in the 14 model year. I don't think I've heard of a 15 plus being affected. My 14 FFV hasn't had any issues thank the Lord.

By the way.... how you liking the SC and the UNI?

You can reset the value with tech stream but I personally its hard for me to trust the hacked versions out there.
My 2010 didn't have any issues at all. Read 7% with the fuel I was and still am using. It would fluctuate, but never outside of the norm.

My 17... Would read funny, high, creep up to mid/upper 20's. They reset it and all was good, then it locked itself at 0%.

Dealership said in July a update was coming out, just haven't heard anything. I inquired, but never got an answer back. Still have to go in for my last oil change, and hopefully they figure it out. Should be going in next week. Waiting to Dap my truck till it goes in.
 

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I am beginning to think it’s how it’s driven after you fuel up. Call me crazy, but my truck had been locked at 20% for a while, and I think it had to do with that I filled up the tank at the gas station that was 0.5 miles from my house and not giving the truck time to go thru it’s calculation. I’ve started filling at a station that is 5+ miles from home. Also to note...the manual calls for an FFV truck to be driven 7 miles or 5 min after fueling.:.im pretty sure now both need to happen instead of one or the other. My truck now consistently reads 11%- which is correct as I use e10- when it was pretty much locked at 20%for a year.
Maybe that is the case. I don't drive much. 14k on my 2017, that will be two years and one month old on the 19th of this month. Fuel station I use is 4.5 miles from my house. Often I fill up, then hit the grocery store, which is only half mile away. Then I head home, which that route is only 4 miles.

I have not monitored it since it locked at zero. I checked it several times, over several months, and it was always at zero, so I stopped reading it as I had read here that once it locks to zero, it needs a reset.

I normally only need fuel every 2-3 weeks.

However, my 2010 I did the same thing with, same fueling station, same grocery store, and it never had an issue, even though it was in the problematic year range.
 

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I had a problem with the alcohol sensor on my '15, rough start and it blew black smoke on start up. The day I took it in for service I got the check engine and traction control lights come on, thank goodness it didn't go into limp mode. Toyota flashed the ECM and I haven't had a problem since but I've heard you can disconnect the battery for 15 minutes or so to let it reset but this sounds like a temp fix so I'd take it in and get it fixed.

My thoughts it's got to have some kind of sensor to detect the gas to alcohol mix.
 

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Discussion Starter · #11 ·
I had a problem with the alcohol sensor on my '15, rough start and it blew black smoke on start up. The day I took it in for service I got the check engine and traction control lights come on, thank goodness it didn't go into limp mode. Toyota flashed the ECM and I haven't had a problem since but I've heard you can disconnect the battery for 15 minutes or so to let it reset but this sounds like a temp fix so I'd take it in and get it fixed.

My thoughts it's got to have some kind of sensor to detect the gas to alcohol mix.
I’m taking it Monday and will post everything that’s done to it.
 

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My thoughts it's got to have some kind of sensor to detect the gas to alcohol mix.
As sundance stated earlier in the thread, there is not alcohol sensor on these trucks.
The ECM uses the air/fuel ration sensors to determine the alcohol content of the fuel after every fill up over a certain number of gallons.
 
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Discussion Starter · #13 ·
My thoughts it's got to have some kind of sensor to detect the gas to alcohol mix.
As sundance stated earlier in the thread, there is not alcohol sensor on these trucks.
The ECM uses the air/fuel ration sensors to determine the alcohol content of the fuel after every fill up over a certain number of gallons.
Was wondering how does a Chevy/Ford measure alcohol % ?
 

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I had the issue not too long ago as well in '15. Took it to the dealership and the ecm was reading alcohol density at like 76% or something crazy like that. Had really rough cold starts but would on do it in cold weather. I think it also affected fuel mileage as well

For the record here is the TSB if anyone else has the issue. I actually had one dealership tell me you couldn't read the alcohol content and I knew they were stupid and I won't be going there anymore. Took it to another dealership and showed them the TSB and truck has been running much better since.

TSB: http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=187888
 

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I had the issue not too long ago as well in '15. Took it to the dealership and the ecm was reading alcohol density at like 76% or something crazy like that. Had really rough cold starts but would on do it in cold weather. I think it also affected fuel mileage as well

For the record here is the TSB if anyone else has the issue. I actually had one dealership tell me you couldn't read the alcohol content and I knew they were stupid and I won't be going there anymore. Took it to another dealership and showed them the TSB and truck has been running much better since.

TSB: http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=187888
That's the one I was thinking of. Didn't know they included the 2015. Thanks!

There has been talk in the past that low pressure from a FFV fuel pump can cause the same symptoms.
 

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Discussion Starter · #17 ·
Truck is fixed, had the newest update installed and reset the alcohol which was 85% and it’s running great(11%) now.
My mechanic said every truck and year will be different just have Toyota scan with Techstream to see if a update has been performed.
 

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Was wondering how does a Chevy/Ford measure alcohol % ?
I believe they once had alcohol sensor but I believe the industry has pretty much switched. If I'm not mistaken, I believe Brazil has lead the way in FFV tech.

https://en.wikipedia.org/wiki/Flexible-fuel_vehicles_in_Brazil

A key innovation in the Brazilian flex technology was avoiding the need for an additional dedicated sensor to monitor the ethanol-gasoline mix, which made the first American M85 flex fuel vehicles too expensive.[12] This was accomplished through the lambda probe, used to measure the quality of combustion in conventional engines, is also required to tell the engine control unit (ECU) which blend of gasoline and alcohol is being burned. This task is accomplished automatically through software developed by Brazilian engineers, called "Software Fuel Sensor" (SFS), fed with data from the standard sensors already built-in the vehicle.
GM is back to using inline fuel alcohol content sensors. There is a lot of guys in the GM forums that believe (and are executing on this belief) if they add this sensor to their non flex fuel 2014+ Silverado, it will now be a flex fuel vehicle and be able to run E85. I would think the ECM would have to be modified as well, but that’s just me guessing.
 

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GM is back to using inline fuel alcohol content sensors. There is a lot of guys in the GM forums that believe (and are executing on this belief) if they add this sensor to their non flex fuel 2014+ Silverado, it will now be a flex fuel vehicle and be able to run E85. I would think the ECM would have to be modified as well, but that’s just me guessing.


There's more than that would need to be changed. The fuel pump and lines for example.
 
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