DIY: Eliminate Speedometer Error doityourself

[BimmerWill]

Any word on if there is a way to fix this on pre-face vehicles?

Sent from S4

[az3579]

If it's a 2001 then I'm sure it would work. The 01's seem to have the later-style software and electronics...

[330i ZHP]

interesting - I have been meaning to see how inaccurate the x5 is

[BimmerWill]

If it's a 2001 then I'm sure it would work. The 01's seem to have the later-style software and electronics...

Awesome. I'll hook mine up after work today hopefully and see if my values are the same as listed.

Sent from S4

[derbo]

Bump, since there is renewed interest in PA Soft editing for the coolant temp

[alexandre]

I've had that on my to-do list for a while. As a data point, I measured my speed on the highway at 108 km/h (GPS) while the cluster (reset avg speed and set the cruise on, so avg = current speed) was saying 114 km/h. 5.55%, which is pretty much exactly what terra said. Excellent research!

EDIT: I just thought this could be because of my 225/45/17 winter tires. Will report back in the summer with 255/35/18 data.

[wsmeyer]

Kevin (RitMusic) and I attempted this but couldn't get past step 1; determining how far off the speedo is.

Armed with his iPhone and my Android running various GPS apps and Torque on mine through OBDII we cruised along at different speeds holding the needle steady but were never able to come to a consensus on the various devices as to exactly what speed we were traveling. At least on his car we concluded that even if it was off, it was accurate to within the width of the needle itself so we didn't mess with it.

Obviously results may vary by specific vehicle.

[terraphantm]

Kevin (RitMusic) and I attempted this but couldn't get past step 1; determining how far off the speedo is.

Armed with his iPhone and my Android running various GPS apps and Torque on mine through OBDII we cruised along at different speeds holding the needle steady but were never able to come to a consensus on the various devices as to exactly what speed we were traveling. At least on his car we concluded that even if it was off, it was accurate to within the width of the needle itself so we didn't mess with it.

Obviously results may vary by specific vehicle.

At normal speeds, the error is pretty small on non-Ms. I never really noticed on my own ZHP until 90ish. On the M3, it was much more noticeable. It might be worth doing the change and seeing if it goes too low -- easy enough to reverse the change.

[NorCalZman]

ah I have been looking for this thread. If I plug my iPhone based OBDII reader into the car and read the MPH that way will it tell me the true MPH or will it match the speedo and its (potentially) incorrect actual speed? If so great, I have everything I need. If not...I am not sure how to determine actual speed.

[gmurphy]

ah I have been looking for this thread. If I plug my iPhone based OBDII reader into the car and read the MPH that way will it tell me the true MPH or will it match the speedo and its (potentially) incorrect actual speed? If so great, I have everything I need. If not...I am not sure how to determine actual speed.

Use a GPS to determine your actual speed then go from there.


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