Correct your speedometer error - no flash or tune required

[FreePenguin]

You'll absolutely get a DTC if you don't follow the instructions and do a PCM relearn after setting the size in the BCM.

Ive never done a PCM relearn, thats a setting on the forescan though correct? so if I change the value, then click PCM relearn, = no issues? if this is correct, im game later. I will get my value GPS though as ive done same thing for my motorcycles and their calibrator offset program devices. I make it like 99.9% accurate with the .01 % more so its like 69.5mph at 70mph cruise.

theres no consequences though from relearning PCM or anything dumb right? gimp/blow/boom.

I am pretty sure everything should be reversible regardless.

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[Spart]

Ive never done a PCM relearn, thats a setting on the forescan though correct? so if I change the value, then click PCM relearn, = no issues? if this is correct, im game later. I will get my value GPS though as ive done same thing for my motorcycles and their calibrator offset program devices. I make it like 99.9% accurate with the .01 % more so its like 69.5mph at 70mph cruise.

It's a procedure you run in FORscan, not a setting.

Please read the OP.

 

[FreePenguin]

I did, and will do it again. Thank you all for answers! next post will be car blew up. jk jk. will report later my success when I do it. I am just super cautious, I changed some settings via forescan was never able to be reverted so anything to do with changes I go with caution.

my abs module is permanently marked as failure/hardware incompatible. so I can no longer even use flashing tools from my ford tune lol. but whatever, still works.

 

[Spart]

my abs module is permanently marked as failure/hardware incompatible. so I can no longer even use flashing tools from my ford tune lol. but whatever, still works.

That kind of sounds a lot like you're using a janky no-name adapter. What ODBII adapter are you using? Does it have a physical switch?

 

[FreePenguin]

That kind of sounds a lot like you're using a janky no-name adapter. What ODBII adapter are you using? Does it have a physical switch?

no. it isnt the adapter, I flashed GT firmware over my ecoboost ABS module lmao. so now my ford tune adapter says INCOMPATIBLE HARDWARE ABS MODULE DOESNT MATCH, FIRMWARE ETC- since it doesn't match, it simply doesn't let me use ford crap. that could be a concern if my engine ever needs a ford perf retune, I will probably refresh abs then reflash but hopefully never needs to come to that.

locks me out of making those changes. but forescan still works on everything official. I talked to friend at ford, he said if I ever wanted ,he should be able to wipe and recode the abs module back to ecoboost firmware, but I cannot put my old abs firmware back on via forescan. it straight denies it.

I got all the performance features and line lock on my 17, I changed my brakes from ecoboost base to GT base calipers because part of me thought, if it think its a GT, and using ABS module thinking it should have gt brakes, I should probably put GT brakes.

Part of me wished I wouldn't of done it though, I dont even do burnouts. I just had the mod itch and didnt know it was irreversible for me using forescan.

 

[Spart]

Updated the OP with information on 2020+ cars. Also updated the calculator to delineate between the two "generations" of as-built.

 

[Drugdealr]

So what do we do in the situation where forscan does not have a relearn function? running the latest build from forscan and got an extended license

.

 

[Spart]

So what do we do in the situation where forscan does not have a relearn function? running the latest build from forscan and got an extended license

.

What ODB adapter are you using?

 

[Fabs5oh]

Need to revive this thread. I just posted in another thread but I believe this may be the more appropriate one to revive.

Having an issue with my 2017 GT PP1 (6-spd M). The car has mild mods (Borla s-type cat back with x-pipe, K&N and stock 3.73 gears that come with the PP1). The car is tuned with an SCT x4 (have both canned 91 tune + custom 93 Dyno tune which it is currently running).

I am running a 325/30/19 rear tire on it which is 3.6% shorter in diameter to the OEM 275/40/19 that comes stock. It was bugging me that the Speedo was off and registering more mileage than actual so I had a buddy change the BCM code to accommodate for the tire change. Speedometer is dead on but car appears to be going into limp mode over 3100 rpm.

Problem is intermittent but is happening more often and I noticed that when it happens the A/F leans out to 20:1 which scares the hell out of me as I don’t want to hurt the motor.

if I revert back to the as built value in the BCM car drives normal again but Speedo is inaccurate again…back to square one. I suspect the tune is fighting the BCM change and that’s why it is going into limp mode. I could try keeping the BCM value and revert back to stock tune but then I lose the custom Dyno tune power gains.

any help would be greatly appreciated.

 

[Spart]

I am running a 325/30/19 rear tire on it which is 3.6% shorter in diameter to the OEM 275/40/19 that comes stock. It was bugging me that the Speedo was off and registering more mileage than actual so I had a buddy change the BCM code to accommodate for the tire change. Speedometer is dead on but car appears to be going into limp mode over 3100 rpm.

Your buddy didn't follow the instructions. This is what happens when you don't do a PCM relearn.

Read the OP. There are complete instructions there. If you only changed the value in the BCM, you stopped short.

 

[Fabs5oh]

Your buddy didn't follow the instructions. This is what happens when you don't do a PCM relearn.

Read the OP. There are complete instructions there. If you only changed the value in the BCM, you stopped short.

Thanks Spart, appreciate the reply. Will go over the thread with him and get him to do the PCM relearn. Weird thing is that he also has a 17 PP1, only changed the BCM value and it didn’t seem to cause him issues.

Weird, but again thanks for the reply.

 

[Spart]

Thanks Spart, appreciate the reply. Will go over the thread with him and get him to do the PCM relearn. Weird thing is that he also has a 17 PP1, only changed the BCM value and it didn’t seem to cause him issues.

Weird, but again thanks for the reply.

The drivability issues don't always manifest themselves, but if he checks his codes I bet he has a P160A DTC (it doesn't throw a CEL.)

 

[Drugdealr]

What ODB adapter are you using?

Resurrecting this. Using the one linked in the OP with the USB cable. Tried today again to relearn as I had to clear a code and saw it was still there from the first time edited over a year ago and couldn’t do a PCM relearn. Updated to the latest forscan, OBDLinkEX, still doesn’t give me the relearn option.

 

[Spart]

Resurrecting this. Using the one linked in the OP with the USB cable. Tried today again to relearn as I had to clear a code and saw it was still there from the first time edited over a year ago and couldn’t do a PCM relearn. Updated to the latest forscan, OBDLinkEX, still doesn’t give me the relearn option.

You've got the best adapter available IMO. It's possible the PCM relearn isn't available through FORscan on your model year yet. Anyone else with a 2021, feel free to chime in.

 

[StanleyDS88]

You've got the best adapter available IMO. It's possible the PCM relearn isn't available through FORscan on your model year yet. Anyone else with a 2021, feel free to chime in.

I have a 2023 GT and I performed the BCM edits like you said, but as with others I do not have the option for a relearn. It did seem to work tho, as my speedometer is dead nuts accurate now. The only DTC's I have are for my tpms since I haven't had a chance to get my new wheels learned.

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