Odometer advancing 20% further than miles covered! (Speedo 20% off too obviously)

[ChuckGm3]

Hi guys, after a few years without a Bimmer, I'm back with a 2002 540iA Sport Package. Picked it up last week as a new daily driver and despite a few issues I'm sorting, I love it.

My Google-fu is pretty strong and I've been able to find solutions to nearly every problem I have, save for this one.

The ODO and Speedo are severely (20%) optimistic. If it was only the speedo I wouldn't give two licks, but it's concerning that for every 10 miles I log in the car, it adds 12 to the odometer. I've confirmed this by comparing GPS data, Google maps distances, and comparing to my other two vehicles. I apologize if there's a thread on this already but every search I've tried only relates to an optimistic speedo, and even then it's only by 5% or so. Can someone please help point me in the right direction?

Thanks in advance!

[f355spider]

The typical error is 5 to 6%. 20% is majorly off. It can be corrected, but requires someone with the software and skills to get into the ECU. There is a correction factor that can be played with. I spoke with Dimitry and stopped by his shop DUDMD Tuning to play with mine a bit several months ago. He got the adjustment a little better on my car, but we ran out of time, and I have not been back to have him mess with it some more. You can probably find someone near you with similar skills.

[ChuckGm3]

Thanks Spider. Is this something any run of the mill “German Auto Haus” mechanic can do these days or am I going to need a specialized tuner? I’m in Southern CA which is practically the roundel capital of the world so I’d imagine it can’t be too hard to find around here. Any help is appreciated.

[TheAngryBear]

Any info on the wheel setup?
If stock then the only thing I can think of is related to f355spider’s idea: if a PO ran a different wheel setup and modified the computers to compensate for that then running normal setup... that would cause over speed reporting. Just like running to small tires on smaller wheels.


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[ChuckGm3]

I should have mentioned these are the stock wheels and tires that came with the car. The previous owner left “The best of Big Band” and Gene Autry in the CD changer so I’m thinking crazy aftermarket wheel sizes were not a thing. I suppose it’s possible... but to require that much adjustment would mean 245/35/24” Donks!

[TheAngryBear]

Probably safe to say that isn’t the case then. Lol

One other thing, maybe, is a dsc/abs issue... the wheel speed sensors go to that and info passed to DME... IIRC... any chance you have the trifecta or similar?
Honestly feel like I am grasping for straws... but eliminate the impossible...


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[ChuckGm3]

Indeed, I do have a DSC issue. I feel like it’s more of a symptom than a cause of the ODO disparity though. When I start the car, DSC passes it’s check and the light goes out... but as soon as I get moving to about 5mph the light comes on and pulling away from any stop light with vigor will confirm that DSC is in fact, disabled, with no way to turn it back on.

Oddly, there is no ABS light or code and a vigorous stab of the brakes will confirm that ABS is working properly. This leads me to believe the DSC issue is not with the wheel sensors but perhaps also with the ECU.

[TheAngryBear]

Hmmm... that got me looking back at the manual: http://www.meeknet.co.uk/e38/E38_DSC_System.pdf
Two thoughts: something wrong with the pulse trigger wheel or the WSS.
Try swapping the left and right rear sensors to see if it is sensor issue.
And check your wheel bearings to ensure they are still sealed.
Forget which rear it is but believe it is those that drive the speedo/odometer.


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[ChuckGm3]

Thanks Bear, I’ll give that a try in the morning. I planned on removing and cleaning the wheel sensors. I’ll check out the bearings as well.

[Aussie528iT]

Since both speed and distance are reading 20% high the instrument panel thinks the car is going faster and further than it actually is.
Is the instrument panel from another car with a different wheel size or diff ratio?
Not sure if the engine revs play a part in calculating speed and distance inside the instrument panel, which a changed diff ratio would effect.
The instrument panel may only need to be recoded/configured using NCS.
Just a couple of other things to consider.

[granlund]

The instrument cluster swap produces similar problems for E36s when swapped between 4-cylinder 318 and 6-cylinder 325/328 but since they are less computerized, it's only off 50% in rpm. If you have stock wheel diameter, stock diff ratio and stock transmission ratio, you can calculate the engine rpm from GPS speed and compare with what is indicated on the dash.

[pleiades]

PA Soft bmwscanner 1.4.0 has an option for setting a speed offset. That might be the answer.

http://forum.e46fanatics.com/showthread.php?t=935613

[ChuckGm3]

PA Soft bmwscanner 1.4.0 has an option for setting a speed offset. That might be the answer.

http://forum.e46fanatics.com/showthread.php?t=935613

I was hoping Carly for iOS could do this but it doesn't look like it. It did confirm for me that the vin from the instrument cluster doesn't match the rest of the vehicle, so that was replaced. I'll have to look into this PA Software and see if that will work for me.

[Aussie528iT]

I don't have PA Soft 1.4 (BMW Scanner 1.4) but with the so called "Full version" as distinct from the "Demo" version, you can reset the VIN to "as new" condition and reset the mileage to zero. You need to do this before you can recode the S/H instrument panel. You can then code/configure it using the info stored in the LCM (Lighting and Check module) which is the alternate info storage area for the instrument panel. This is needed for redundancy purposes so you can code a replacement instrument panel or LCM. They provide back up storage for each other.
You may need to use PA Soft 1.4 to reset the panel and then use NCS to code the panel.
I'm not sure if you can actually code a new module with PA Soft 1.4, rather than just change the existing settings already coded into a module. Others who have used PA Soft 1.4 will know.

Hope this helps

[ChuckGm3]

I don't have PA Soft 1.4 (BMW Scanner 1.4) but with the so called "Full version" as distinct from the "Demo" version, you can reset the VIN to "as new" condition and reset the mileage to zero. You need to do this before you can recode the S/H instrument panel. You can then code/configure it using the info stored in the LCM (Lighting and Check module) which is the alternate info storage area for the instrument panel. This is needed for redundancy purposes so you can code a replacement instrument panel or LCM. They provide back up storage for each other.
You may need to use PA Soft 1.4 to reset the panel and then use NCS to code the panel.
I'm not sure if you can actually code a new module with PA Soft 1.4, rather than just change the existing settings already coded into a module. Others who have used PA Soft 1.4 will know.

Hope this helps

Thanks Aussie. I hope someone can confirm this also. I spoke to my local BMW shop and they said they only thing they can do with an instrument cluster and their computer, is transfer the miles from one to another. He doesn't think it will be possible. I'm not sure if that means he's not able to, doesn't know that it's possible, or just doesn't want to. But it looks like I'm stuck doing this myself unless I can find someone local who has experience with this.