[TunafishE93]

My car was saying it was going 4 mph faster than actual. Was able to get digital read to have the correct speed but until now not the analog. Its saying about .5 mph faster than actual at 70 mph now. He's the instructions for bimmercode app.
Car used, 2012 E93 335I N55 Automatic.

Go into "Instrument Custer".. Mine is "KMBI_PL2".
Go into expert mode
Go into "3002 WEG"
Go into "C08_K_ZAHL_TACHO"
Select "Custom Value"
Input "A4" on top and "61" on bottom
Select "OK"
Go back and select "C08_K_ZAHL_TACHO_KOMPL"
Select "Custom Value"
Input "5B" on top "9E" on bottom
Select "OK"
Go back to "Instrument Custer" menu
Change "Speedometer Correction" and "Digital Speed Correction" to "Active" if not already
Then press "code" on top
Test.

I got these values from another thread which is linked. I am not sure what they mean but worked for me (is still half mile off).

https://www.e90post.com/forums/showthread.php?t=688219

[MadJoe]

I used this on my 2011 328xi and went from 7mph off to only 3, so thank you! I know it isn't perfect, but it's a heck of a lot better than it was.

[MadJoe]

Using your instructions and the spreadsheet found here, I was able to calculate the perfect settings for my car and now have a speedometer that agrees with my GPS!

This thread should be stickied, the link I provided has instructions for doing this via NCS Expert so you don't have to have the Bimmercode app.

[nsjames]

perfekt toolbox makes this remarkably easy if you already have a PC inpa setup.

[MadJoe]

Originally Posted by nsjames

perfekt toolbox makes this remarkably easy if you already have a PC inpa setup.

I can't find a download for that that doesn't require me to make an account with the website, nor can I easily find instructions on how to use it. I'm going to stick with using the Bimmercode app (since I paid for the licenses) and continue to point people to the instructions and spreadsheet for NCS Expert that I linked for the time being.

[nsjames]

https://www.drive2.com/l/496203276497191008/

[colorado.e9x]

Will this work with the digital cruise control readout? Every time I set it I notice its ahead by 3mph

[MadJoe]

Originally Posted by colorado.e9x

Will this work with the digital cruise control readout? Every time I set it I notice its ahead by 3mph

My cruise control shows the same speed as my speedometer, but it was never off from that to begin with. Not sure if it will correct it.

[colorado.e9x]

Just finished up doing this and I'm glad to say that it fixed everything including the cruise control 🙏🏼

[Chriscabob]

Thanks! E92 2010 is now accurate

[goondout]

New to forum and new to BMW. I used Perfekt application to adjust speedo corrections. Was able to get within 1mph of GPS on digital display and cruise bug (displayed speed 1mph faster than GPS), but the analog needle was showing slightly higher 1-2mph than the digital. Would value any tips to bring the analog needle into agreement with the digital and cruise bug.

[goondout]

Update: as stated in prior post, with cruise/digital speedo set at 60mph, the GPS was 1mph slow (59mph on satellite app). I decided to experiment by lowering each "displaying" value in Perfekt by 1/60, or 1.7% rounded to nearest tenth. The screenshot here. These settings were uploaded and now the digital/cruise are in perfect agreement with GPS. The analog needle is still showing a bit over 1mph faster than the digital/cruise. I see there is a Cruise control parameter that can be customized in KOMBI but not seeing a direct correlation to how they interact with either the digital or analog speedometer displaying values.

I assume most, or all of the info I am reporting here is commonplace to this forum, but I would highly value feedback from experts on how to fine-tune and get the analog needle to exactly agree with the cruise bug and digital displayed speed. Cheers

[Mike K]

Nice work. I read somewhere that the NHTSA has a law that US cars must always over report MPH speeds and never underreport. I believe what you’re experiencing is common to all US cars.

After tweaking attempts my e91 always reports 2 mph over and I just factor this into my driving and check it against Waze if needed.

[goondout]

Thank you for the reply - I will have to look for details on the law. I assume that was put in place to protect Odometer integrity - which I can certainly understand. One could rationalize: this process of dialing in my particular car's speedometer (with all things considered like tire diameter, computing tolerances, etc.), that I am acting in good faith to the law... I would value knowing if anyone has ever been subject to discipline for setting values slightly below the default lower bound values, to achieve a match with a satellite source of truth. Hmmm. Perhaps I should edit the prior posts, so not to draw unwanted attention. I was only sharing the amount of adjustment needed for my specific application, to bring the speed in line (so the driver doesn't have to account for the offset).

On my GMC pickup, I had to do the same adjustments with a tuner in order to get the displayed Speedo to match GPS. The adjustment is made by telling the ECU a different tire diameter, so you really have no awareness of the "default" lower bound values.

Cheers

[Mike K]

I don’t think this is a law that the consumer would run afoul of. Rather, an auto manufacturer’s responsibility.

[goondout]

Originally Posted by Mike K

I don’t think this is a law that the consumer would run afoul of. Rather, an auto manufacturer’s responsibility.

That makes sense. I am well outside of my lane here!!