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Afrothunderr86
04-07-2008, 11:21 PM
I was talking to my mechanic, who is a bmw specialist, and he was telling me about how US spec bmw's are purposefully programmed to have speedomiter error to help people drive slower, so i checked it against my gps and saw that when the speedo says 80 im actualy doing about 75. i actualy got the speedo up to 140, gps said 130. everything on my car is stock, wheels tires, trans, rear diff. its a 2001 330ci sports package. anyone know if i can get it reprogrammed or fixed somewhere?

sunny_j
04-07-2008, 11:39 PM
i think you cant do anything about it. just drive 5kms faster:thumbup:

no8080
04-08-2008, 12:50 AM
It's neither specific to the US or BMW's, speedo's tend to give a higher speed reading than you are really going, for the simple reason; better to be going slower than you think you are than going faster than you think you are. It is a historical safety issue, as well as the prefered option under UK law for UK cars. Speedos of old where inaccurate, the gave different levels of error depending on your speed.

As long as the speedo is within 10% of your true speed, it is considered acceptable. For speeding tickets in the UK you get 10% +2MPH error allowed on your speedo before you will get a ticket. Unless the cop is in a bad mood, :D.

Funny thing is, if you set the speed limitor option to reflect your current speed, it will give you your true speed, it shows how much your speedos out, ie when I have cruise on at 60MPH on the speedo and I set the limitor to the current speed it read 57MPH. I know the 57MPH is accurate on my car because I have driven through several speed check radars and it says 57MPH. We have loads of the speed check radars near me, they display your speed on a large board for everyone to see.

AzNMpower32
04-08-2008, 06:19 AM
For odometer purposes, the car knows its true speed under the hidden OBC menus. I compared this "true" speed to that of my Garmin sat nav, and the two match up perfectly.

golfnut802
04-08-2008, 06:27 AM
For odometer purposes, the car knows its true speed under the hidden OBC menus. I compared this "true" speed to that of my Garmin sat nav, and the two match up perfectly.

Is there a way I can get to the hidden menus to check my speedo? Thanks.

AzNMpower32
04-08-2008, 11:56 AM
Instructions are in the E46 wiki: http://www.bimmerfest.com/wiki/index.php?title=BMW_E46#Hidden_Onboard_Computer_Fu nctions

Slightly different for newer BMWs. Since we don't have a key, press and hold the reset button before putting in your key fob. The lock code you must enter is the sum of the last 5 VIN digits. The actual speed is menu item 8.0 (not 7.3 like the E46/E83).

sillycar
04-09-2008, 04:53 AM
I thought mine read slower. I have had several tickets and could have sworn my speed was only 120 km/hr when I got a ticket for 125 km/hr to break the threshold and make it harder to reduce to 115 in court