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

[mepot101]

I set mine to 950, but it still shows too high.
Pump reading tells me I'm getting ~43, the dash still shows 46mpg.
How low should I go to get it closer?
I mostly drive red light to red light in Orlando, with an occasional highway trip.

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[jb_cb900]

Tried this in my XLT with the smaller display and it never entered Engineering Test Mode. I don't have push button start, but did turn key to the run position with the OK button pressed for well beyond 7 seconds. Very disappointed.
Does the smaller display support Engineering Mode?

 

[HeyBales]

Tried this in my XLT with the smaller display and it never entered Engineering Test Mode. I don't have push button start, but did turn key to the run position with the OK button pressed for well beyond 7 seconds. Very disappointed.
Does the smaller display support Engineering Mode?

Hold OK button while key turned to ON - not Run.
Green ET will show up on display when you let go of OK after 7 seconds.

 

[Rallywagon]

I have an Ecoboost Lariat and just could not get into the ETM. My display just scrolled between the Seat belt [OK], Full Accessory Power [OK], and a third I cannot recall while typing this. I tried it with the engine started and not - no dice. I gave up after 1/2 dozen attempts before I really screwed something up.

One of my Forescan to do's is to disable that bloody seat belt warning, just haven't got around to it yet. It just moved up on my priorities list.

There is a procedure in the owners manual to do this involving buckling and unbuckling the seatbelt. It took me several tries but now I don't have to listen to the chime down my long driveway after getting out to check the mail when I get home.

 

[jb_cb900]

Got it! Thanks
A little persnickaty. ET appears in about 4-5 seconds. ON and RUN refer to the same key "position" with engine not started.

 

[MCIAD]

There is a procedure in the owners manual to do this involving buckling and unbuckling the seatbelt. It took me several tries but now I don't have to listen to the chime down my long driveway after getting out to check the mail when I get home.

Gonna have to look that one up. Thanks for the tip!

 

[Bill Quattlebaum]

I set mine to 950, but it still shows too high.
Pump reading tells me I'm getting ~43, the dash still shows 46mpg.
How low should I go to get it closer?
I mostly drive red light to red light in Orlando, with an occasional highway trip.

43 divided by 46 = 935

 

[Ozarkbeard]

...One of my FORScan to do's is to disable that bloody seat belt warning, just haven't got around to it yet. It just moved up on my priorities list.

Not having FORScan, I manually disabled each individual seat, using the buckle/unbuckle method. It's nice to not have that shit going off when I drive up my empty private road to get my mail. At least until a future time when I take the truck in for yet-another-software-update and the dealer wipes the preferences.


I always wear my seatbelt when leaving my private property. One would be a complete idiot to not wear one; having seen so many horrible accidents where people didn't and were needlessly killed.

[Edit: removed/moved some commas. ]

 

[wax87]

MPG Correction Tutorial
If your Ford Maverick displays an inaccurate MPG, you can correct it by adjusting the AFE bias in Engineering Test Mode. After calculating my truck's MPG at the pump, I discovered the displayed MPG indicated a value approximately 1.2 MPG higher than the actual value (about 4-5%)

Steps
Follow these steps to enter Engineering Test Mode and fine-tune the AFE bias for a more accurate MPG readout.

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.
2. Adjust the AFE Bias
   • Use the Up/Down buttons to navigate to the AFE Bias option.
   • If you haven't made adjustments yet, the default value will be 1000 (representing 100%).
   • Use the formula or Siri Shortcut below to adjust your AFE bias so your truck displays a more accurate MPG value.
   • Turn the truck off to exit Engineering Test Mode.
3. Bonus Features
   • Engineering Test Mode also provides access to diagnostic trouble codes, RPM, coolant temperature, and other valuable data.

Calculation Formula
Current AFE Bias value X Calculated MPG / Displayed MPG = New AFE Bias Value

Pro Tip
I recommend repeating this process multiple times over a few fill-ups to calculate a more accurate average. When I did the math, I noticed some variance, so taking multiple readings will help you get a more precise result.

Siri Shortcuts
For iPhone users I’ve included a Siri Shortcuts link below that quickly calculates the new AFE bias value, even if the current bias differs from the default value of 1000. This shortcut makes fine-tuning your MPG quicker and easier on the go.

https://www.icloud.com/shortcuts/d392c91a176448eba3845e6e2971a809

Photos
Main Engineering Test Mode Screen

AFE Bias menu.

I have already adjusted mine from 1000 to 950 (100% to 95% readout)

Diagnostic Trouble Code Menu. There are many more menus as well.

Siri Shortcuts app I built.

View attachment 187331

Hope this helps!

If you disconnect the battery, does it reset to 1000 or does it remember your setting?

 

[HeyBales]

mepot101 said:
I set mine to 950, but it still shows too high.
Pump reading tells me I'm getting ~43, the dash still shows 46mpg.
How low should I go to get it closer?
I mostly drive red light to red light in Orlando, with an occasional highway trip.

43 divided by 46 = 935

Was thinking about this - like the OP shows, the formula changes if you already had a changed AFE figure.

If dash mpg was based on 950 AFE already, then unchanged AFE would have caused a 48.4 mpg (46/0.95) reading.

So new would be 43 / 48.4 = 888

Pump MPG / (Dash MPG / Current AFE (/1000)) = new AFE (*1000) is the long version.

Which simplifies to the OP formula.

 

[HeyBales]

If you disconnect the battery, does it reset to 1000 or does it remember your setting?

It has been commented elsewhere when the battery is replaced your DTE is way off because the learned values are lost, but IIRC when ones looked this AFE was still there. And within so many miles the DTE starting getting better estimate.
It just is used with the DTE logging and math.

 

[Bill Quattlebaum]

Was thinking about this - like the OP shows, the formula changes if you already had a changed AFE figure.

If dash mpg was based on 950 AFE already, then unchanged AFE would have caused a 48.4 mpg (46/0.95) reading.

So new would be 43 / 48.4 = 888

Pump MPG / (Dash MPG / Current AFE (/1000)) = new AFE (*1000) is the long version.

Which simplifies to the OP formula.

I'm not sure about that. I use actual mpg divided by computer mpg to get AFE bias number. In your example it's saying the reading is optimistic by 11.2 percent. When I first checked mine, it was off by about 6.5 percent and has improved some since then. I haven't heard of anyone's being off by that much. I think it would be better if Ford would just set it at 950 at the factory.

 

[imboden013]

I'm not sure about that. I use actual mpg divided by computer mpg to get AFE bias number. In your example it's saying the reading is optimistic by 11.2 percent. When I first checked mine, it was off by about 6.5 percent and has improved some since then. I haven't heard of anyone's being off by that much. I think it would be better if Ford would just set it at 950 at the factory.

I don’t know how all you guys are coming up with the amount that Mav’s computer is off. There are all sorts of variables each time you fill up. Sometimes my hand calculations show I’m getting less mpg(which is not consistent in how much) then some times my calculations show I’m getting more. With that small of a tank if you get a few tenths more or less in the tank it will make your calculations way different from the computers calculation. Example the other day I’d traveled just 77.2miles and wanted to top off for a trip the next day. I filled up and after filling same as usual the pump showed something like 1.35 gallons, that’s like 57.2 mpg. I pulled the nozzle out a bit more and squeezed in a little more to get to 1.48 gallons that’s 52 mpg the trucks computer showed 44.7mpg so either figure I used was way different. What I use my computer or my hand calculations for is to tell me if something serious is going on. If my mpg seriously drops over a full tank or so then I look for why.

 

[Bill Quattlebaum]

I just like for the computer reading to be accurate. You should never make changes just based on 75 or 100 miles. I think use at least 2 full tanks before making any changes. The fact is that the factory setting is too high. Most people on here say that about 950 is a lot more accurate number than the factory setting of 1,000. Of course there are many factors that can make your mileage go up or down. My truck is averaging around 29 mpg and I am happy with that.

 

[AlsMaverick]

I don’t know how all you guys are coming up with the amount that Mav’s computer is off. There are all sorts of variables each time you fill up. Sometimes my hand calculations show I’m getting less mpg(which is not consistent in how much) then some times my calculations show I’m getting more. With that small of a tank if you get a few tenths more or less in the tank it will make your calculations way different from the computers calculation. Example the other day I’d traveled just 77.2miles and wanted to top off for a trip the next day. I filled up and after filling same as usual the pump showed something like 1.35 gallons, that’s like 57.2 mpg. I pulled the nozzle out a bit more and squeezed in a little more to get to 1.48 gallons that’s 52 mpg the trucks computer showed 44.7mpg so either figure I used was way different. What I use my computer or my hand calculations for is to tell me if something serious is going on. If my mpg seriously drops over a full tank or so then I look for why.

Agree with this. The way to get rid of that error is to keep a running total of both miles traveled and fuel added to the tank. It doesn't matter if it's full or not. The more readings you get, the less the error.
Keep two columns (spreadsheet makes it easy) one labeled "Miles Traveled Since Last Fill" and the other "Fuel added at This Fill".
Keep a running sum and you will see that you average MPG gets very accurate.

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