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

Well, I haven't been having as much luck with mine. 2013 CM, 175k miles ish. I did the relearn about a month ago with my bidirectional unit (Mucar VO7S). Data stream shows alcohol at 0 and both FTs around .078ish. It ran fine for a day or two but then the hard starts came back. Got hold of Techstream and a cable and figured I'd try it that way in case the other tool wasn't up to snuff, but results are the same. Odd thing is I've never had an mpg issue, it always sits around 15.3, according to the dashboard. Otherwise all the other symptoms are there - extended starts, misfires on some starts, rich fuel exhaust. I've got a fuel pump arriving this weekend (DeatschWerks DW300C) so I'll replace that and clean the tank out as well.
Beyond that I'm stumped. Like Ohannon7 I've wondered if swapping to a non FF ECU is possible. My other thought is taking it to a tuning guru explaining the issue and asking if they could just disable the unwanted E85 fuel maps and/or functions altogether.

 

@e30cabrio was able to successfully swap in a non-flex ecu recently. Maybe he can give a quick list of what it took to accomplish the task.

 

Interesting, read through what he said in the General Supercharger Thread so I started doing some research and stumbled on something odd. This ECU PN 896610CM34 replaces previous ECUs for 2012/2013 5.7L - the interesting thing being that Toyota states it is for both FFV and non FFV... Anyhoo, I figure if I can find one from a non FFV with 4x4, with Crewmax, with Tow pkg I'll give it a shot. I'd like to find a PN# for the one I want first though, would make it easier

 

Yeah, that's where his posts were made. I figured having the info here would be useful as well.

 

Also to note, the Toyota part number is the same for 4x4 and RWD, which is surprising to me. So it seems Crewmax and tow pkg are the only differentiators. Maybe.

 

Update for those interested:
I purchased a non-FFV ecm from a yard with a truck that was, in every way I could find, identical to mine.
My FFV ECM pn# is 89661-0CM74
The donor ECM pn# is 89661-0CM34

Steps taken so far -
1. Installed donor ECM
2. Via shorting OBD pins 4 and 13 I was able to get the immobilizer ecu and engine ecm to communicate. Without doing this you will get an IMMO DCT
3. Written my VIN to the donor ecm using Techstream
4. Attempted to start the truck. Will not start, sounds as if it is missing fuel, and it throws the generic P1604 startability malfunction code. This code can be thrown for dozens of reasons and really means nothing other than your vehicle won't start which we already know. However I have found cases of this code and scenario appearing when people replace their ABS ecu. So preliminarily I may still have an issue with all the ecus in the truck shaking hands with the new ecm.

 

non-FFV activates the fuel pump differently than FFV. There was some info about it in the other thread, but you basically need to find a new way to kick the pump on, ie: run a wire back to it that's switched 12v. @e30cabrio

 

Interesting, was that in the supercharger thread? Thanks for the lead

 

yes. General Supercharger Thread: Non-FFV ECU swap.

 

Alright so basically Toyota in their infinite wisdom decided to handle the switching of relays related to the fuel system differently between the 3UR-FE and 3UR-FBE. So the root solution to this is to simply bypass it by running the fuel pump off of another switched source. I'm still a little confused on this though because with the ign on I am currently getting 12vish at the fuel pump relay.

 

I'm hoping there's a way to jump something in the underhood fuse box that will allow the non-ffv ecu to turn on the fuel pump using the stock wiring, but I haven't had time to look through the wiring diagrams yet. Maybe someone else will figure it out while I'm procrastinating.

 

I checked my ethanol percentage yesterday to see where it's at. It's still reflecting 0% ethanol. I believe when I had my truck tuned they were able to somehow lock it at 0%. Truck was tuned March of last year and has remained at 0% ever since. Might be another option for a fix as well. Truck was tuned with hptuners at a local shop here in Phoenix.

 

HP tuners can’t reset it or lock it or anything else. At least according to OTT.

 

As long as you can find a circuit that is hot while cranking, it shouldn’t be that difficult to wire up. Just run it through a relay capable of supporting the draw and that’s all it should need.

 

My Launch scan tool shows 0% as well, I believe it might be an issue with the scanner.

 

I can check with the tuning shop to confirm. I'm pretty sure they use hptuners. Shop was dyno comp in scottsdale, az.

 

I used a Launch X431 to reset my Tundra a few months ago. Truck showed 0% alcohol and 0 LT fuel trim when I started it after the reset. Numbers fluctuated a little bit while driving but not drastic. After a few months now it's been stable at 0% and LT trim in low single digits.

Today I used the XTool D7 to reset my Sequoia. When I started engine after resetting learned data, LT trim was still -24 and alcohol started at 0% but quickly rose back to 85 while idling. Short test drive numbers stayed that way at basically the original values from before the reset. I reset it again then went for another drive. This time alcohol stayed at zero but it took a few minutes for fuel trim to drop out of the -20s. Then LT trim would go to around 5 when on the throttle but drop back to -21 or so when coasting. After about 15 miles the LT trim seems to be stabilizing better in low single digits. Anyone else have to reset more than once or have numbers fluctuate so wild for the first few miles after using the D7 tool?

 

Here's the bit under the hood in question, note the asterisks in the top right that indicate fe vs fbe. I'm not very good when it comes to this part, but I'm trying to understand the differences between the two in hopes of finding a solution.

 

Looks like on the FFV power goes from the f/pump relay to the c/opn relay, then to the fuel pump controller, and on the non-ffv it just goes from the f/pump relay to the controller. Both ecus trigger the f/pump relay, so maybe if you remove the c/opn relay and jump pins 3 & 5, when the ecu triggers the f/pump relay power will get through to the pump controller.

disclaimer: i've been up all night and Im not an electrician, so if you burn your truck down it's not my fault

 

Alright, I gave that a try but no luck. However it was interesting. Previously when trying to start with all normal things in place, I would get the extended starter run, where it keeps going for several seconds after you turn the key even if you let go. The cel light was also on. With the c/opn relay removed and 3/5 jumped the cel went out and the extended starter run went away

 

damn. i was hoping it would be that easy

 

Well this is baffling. Yesterday I disconnected the neg batt terminal and left the battery connected to the charger all night so I would have a full charge to work with today. Now both ECMs (old one and donor) will not communicate with Techstream or my other scanner. The donor was the one in the truck all night, the old ecm has just been sitting on the bench for a few days. I wonder what has gone sideways

 

If it's with both ecus, check fuses under hood and dash. Check for 12v and ground at the obd2 plug. I forget which pins

 

EFI 1 was blown

 

5/23 - Well, in the last several days I put the old ecm back in so the truck could be used. I also changed out the fuel pump and bypassed the internal filter using an external one. While I was down there I went ahead and tapped the power line for the pump so I could manually connect it if needed.Truck has run much better than it did before and I've seen noticeable increase in mpg. That said, I'm still getting random misfire starts here and there, just less often than before. I have a suspicion (like others) that the "lifetime" fuel filter in the tank is a crap idea and they figured oh well we'll just gouge them for pump replacements.

Today I decided to start again with the donor ecm and now the odd behavior has changed. Step by step I - disconnected the battery, removed old ecm, installed donor, reconnected battery, jumped 4 and 13 on obd, put key in ignition and.... when I turn the key to the on position(not start) the truck tries to start itself and the starter runs till I disconnect the battery (does not respond to key turning off). So I removed the paperclip and tried to turn to the on position again and it does the same thing.
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These things are baffling. I put the old ecm back in and everything works as expected but no starter now, so whatever the trouble was with the starter running is related directly to the donor. But the last few times I worked with it it did not have this problem. The only thing that has changed since then is the fuel pump. Weird.

 

Did you guys that bought the Launch X341 have to buy the reset function. And which one did you buy if you did

 

I didn't need extra purchase. Just did updates, plugged into truck while in range of WiFi, then it asked for more updates. Then I was finally able to find reset options.

 

5/24 - Whatever it was that happened seems to have roasted the starter solenoid, lovely smell.

 

Well this is just a bummer. I was having a lot of hope for you in your process.

 

Still working on it, I moved it over to a new thread so I don't keep clogging this one up - ffv-to-non-ffv-ecm-swap-attempt