MPG Correction Tutorial - AFE Bias Adjustment (via Engineering Test Mode)

[KrS]

Yikes, I had to run 935 for the winter, might have to adjust that up to 965 or so for the spring. (965 was what I ran before cold winter badness)

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[rungorillarun]

I have a 2025 and was having a lot of trouble getting this procedure to work. The screens are very different from prior years. I think I have figured it out for 2025 model year.
Procedure to access Engineering Test mode is the same. Hold OK and press start- keep holding OK until a grey ET shows up on the dash. At this point I waited for a while for the alerts to cycle through. After I cleared the seat belt warning, I still had ET on the dash but had a blank screen. When I toggled up/down with the button, I saw the screen like, acknowledge that I changed something but I still couldn't see anything.
Next, I hit the hamburger stack on the right of the steering wheel- The three stacked lines. That was the needed input. Engineering test screens became visible and I was able to edit my afe bias down to 950 (all of my actual mileages have been 5% off).

tldr: hold ok to enter ET mode. if you can't see the info screens, hit the three stacked lines button.

 

[Montuna]

So, I tried this but had to:

1. Press and hold right OK button
2. Press and hold brake(didn't work w/o this)
3. Hit start button (continuing hold of OK button till ET showed up)

And then I got the ET bit (with the seat belt warning, etc.) My MPG bias showed up as 1000, and (with my one fill up) it was pretty much DNO, so I left it alone.

What I'd seen was that for the hybrid you had to not hold the brake, but that didn't work for me, I had to hold the brake, and start the car, all while holding down the right OK button till the ET showed up. I didn't need to engage the hamburger stack.

I am wondering if this is available multiple ways, or if software updates change this... My software updated a week ago.

 

[DScruggs]

Most people, myself included are happy with the setting at 950 (95%).

Pretty much all the trucks are off by 5%.

I'm sure there's an exception here and there.

Yeah, I guess I am one of the exceptions. I am averaging being over by 15%.

I will adjust to about 875 and monitor the results.

 

[Green2025xl]

Anyone with an idea for xl 2025 hybrid to get to test mode I can not get it to work as described above never mind finally got it

 

[Sloberdog]

Tried every combo on my 2025 Lariat Hybrid....could not access the Engineering Test Mode. Has anyone figured out if even possible in the 2025 Hybrid models? From my experience, it does not appear to be possible.

 

[Tbone289]

Tried every combo on my 2025 Lariat Hybrid....could not access the Engineering Test Mode. Has anyone figured out if even possible in the 2025 Hybrid models? From my experience, it does not appear to be possible.

Evidently @Green2025xl in the prior post did.

 

[Sloberdog]

Tried it...did not work on my 2025 Lariat Hybrid. Mine is CA CARB compliant...so maybe that has something to do with it. Maybe it is a CA thing.

 

[DScruggs]

Tried every combo on my 2025 Lariat Hybrid....could not access the Engineering Test Mode. Has anyone figured out if even possible in the 2025 Hybrid models? From my experience, it does not appear to be possible.

I have done it 4 or 5 times on my 2025 Lariat Hybrid.

 

[REDRUM]

If everybody is off and little, would installing larger tires make the MPG closer to actual?

 

[SafetyGuy]

Tried every combo on my 2025 Lariat Hybrid....could not access the Engineering Test Mode. Has anyone figured out if even possible in the 2025 Hybrid models? From my experience, it does not appear to be possible.

Hiya @Sloberdog.

Try this, I finally figured out how to access ET 2 minutes ago on my 2025 Lariat.

I did sit down in my truck and ran through the process to ensure accuracy for my truck.

(Edit-for spacing and ease of reading and format)

1. Already have power "on", in the vehicle

2. Turn power "off (edit-keep your screens on..do NOT turn your screen off!)

3. Press "ok" button

4. Press "brake" with foot

5. Press "power on" button to turn truck on

6. Release "power on" button

7 Release "brake" with foot

8. "ET" letters should appear in 3 or 4 seconds...you may need to hit "OK" to clear seat belt etc screens, but "ET" SHOULD remain once you clear them

9 carry on with setting your "AFE" fuel adjustment etc as you see fit.

Please let us know if this works for you, and good luck,

Andy

 

[Sloberdog]

Hiya @Sloberdog.

Try this, I finally figured out how to access ET 2 minutes ago on my 2025 Lariat.

I did sit down in my truck and ran through the process to ensure accuracy for my truck.

1. Already have power "on", in the vehicle
2. Turn power "off"
3. Press "ok" button,
4. Press "brake" with foot
5. Press "power on" button to turn truck on
6. Release "power on" button
7 Release "brake" with foot
8. "ET" letters should appear in 3 or 4 seconds...you may need to hit "OK" to clear seat belt etc screens, but "ET" SHOULD remain once you clear them
9 carry on with setting your "AFE" fuel adjustment etc as you see fit.

Please let us know if this works for you, and good luck,

Andy

Wow Andy! That worked. Thank you for taking the time to explain your detailed procedure. On behalf of all the 2025 model year owners....thank you! - Gabe

 

[SafetyGuy]

Wow Andy! That worked. Thank you for taking the time to explain your detailed procedure. On behalf of all the 2025 model year owners....thank you! - Gabe

Of course you are most welcome, Gabe!

I did just go back into my post now that I am home, just to clean it up a bit, and some standard neatness formatting and one clarification where I thought a misunderstanding could derail the instruction.

Cheers, and happy Maverick-ing!

Andy

 

[quayz]

I have done it 4 or 5 times on my 2025 Lariat Hybrid.

IT MIGHT BE ME, but i tried several times had no success getting ET
to display what am I missing?

 

[HeyBales]

IT MIGHT BE ME, but i tried several times had no success getting ET
to display what am I missing?

Hopefully not following the 2025 Lariat ones!
These from 1st post should work, if you understand you are wanting the On position, not Start, not Acc.
Can't tell if you have keyed XL/XLT or Lariat trim keyless.
You do have to let go of OK button after the 7 sec, to see the ET then appear.
Door closed?

1. Enter Engineering Test Mode
   • With the truck off, press and hold the right-side OK button on the steering wheel.
   • While holding the OK button, press and release the Start/Stop button (or turn the key to the "on" position). You do not have to start the engine.
   • Continue holding the OK button for 5-7 seconds until you have entered Engineering Test Mode.

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