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Discussion Starter · #1 ·
The delta between my actual speed (GPS derived) and my speedo is annoying. I have read that the BMW speedo reads between 8 and 10% high. I also read Alex Roy's book where he installed a sensor (wheel something) and it had a digital readout of his actual speed.

Is there a way to correct the speedo or do you need to go aftermarket and use the wheel speed sensor?
 

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I have been looking into this also, I don't know if its possible to adjust it in the dash cluster test 07.3 or 07.058(one of those two).

First the mars lander calculations and now BMW speeds, It must have been the same NASA employee.
 

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Discussion Starter · #3 ·
I have been looking into this also, I don't know if its possible to adjust it in the dash cluster test 07.3 or 07.058(one of those two).

First the mars lander calculations and now BMW speeds, It must have been the same NASA employee.
lol - and you are waaaay farther into this than me. I assume that the input is digital?
 

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I will try to find the instructions again, I had to run off to a softball game so I couldn't look for them earlier.


E39 Instrument cluster test functions

Test functions
<TABLE id=table10 borderColorDark=#3f617e width="100%" borderColorLight=#000000 border=0><TBODY><TR><TD vAlign=top align=left bgColor=#ecf2f1>Menu</TD><TD vAlign=top align=left bgColor=#ecf2f1>Sub menu</TD><TD vAlign=top align=left bgColor=#ecf2f1>Sample</TD><TD vAlign=top align=left bgColor=#ecf2f1>Meaning</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 1: Vehicle specific data</TD><TD vAlign=top align=left bgColor=#ecf2f1>1.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>12345</TD><TD vAlign=top align=left bgColor=#ecf2f1>VIN</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>1.1</TD><TD vAlign=top align=left bgColor=#ecf2f1>4812</TD><TD vAlign=top align=left bgColor=#ecf2f1>Body number</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>6_1.2</TD><TD vAlign=top align=left bgColor=#ecf2f1>834762</TD><TD vAlign=top align=left bgColor=#ecf2f1>Part number of cluster</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>1.3</TD><TD vAlign=top align=left bgColor=#ecf2f1>010203</TD><TD vAlign=top align=left bgColor=#ecf2f1>Coding/Diagnosis/Bus index</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>1.4</TD><TD vAlign=top align=left bgColor=#ecf2f1>3495</TD><TD vAlign=top align=left bgColor=#ecf2f1>Manufacturing data (calender week/year</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>1.5</TD><TD vAlign=top align=left bgColor=#ecf2f1>04_600</TD><TD vAlign=top align=left bgColor=#ecf2f1>Hardware/software number of cluster</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>3_1.6</TD><TD vAlign=top align=left bgColor=#ecf2f1>415_06</TD><TD vAlign=top align=left bgColor=#ecf2f1>Injection status, number of cylinders, engine factor</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 2: Cluster system test</TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>Activates test for gauge drivers, indicators and LEDs</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 3: SI data</TD><TD vAlign=top align=left bgColor=#ecf2f1>3.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>1500</TD><TD vAlign=top align=left bgColor=#ecf2f1>Litres</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>3.1</TD><TD vAlign=top align=left bgColor=#ecf2f1>0</TD><TD vAlign=top align=left bgColor=#ecf2f1>Periodic inspection days (not applicable for US)</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 4: Fuel consumption data (current)</TD><TD vAlign=top align=left bgColor=#ecf2f1>4.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>0267</TD><TD vAlign=top align=left bgColor=#ecf2f1>26.7 litres/1000km</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>4.1</TD><TD vAlign=top align=left bgColor=#ecf2f1>0073</TD><TD vAlign=top align=left bgColor=#ecf2f1>7.3 litres/hour</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 5: Fuel consumed/distance travelled</TD><TD vAlign=top align=left bgColor=#ecf2f1>5.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>0195</TD><TD vAlign=top align=left bgColor=#ecf2f1>19.5 litres/100km</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>5.1</TD><TD vAlign=top align=left bgColor=#ecf2f1>226</TD><TD vAlign=top align=left bgColor=#ecf2f1>Momentary distance to go (22km)</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 6: Fuel level sensor input in litres</TD><TD vAlign=top align=left bgColor=#ecf2f1>6.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>237415</TD><TD vAlign=top align=left bgColor=#ecf2f1>Fuel level averaged.
LH sensor input = 23.7 litres - RH sensor input = 41.5 litres
</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>6.1</TD><TD vAlign=top align=left bgColor=#ecf2f1>0652</TD><TD vAlign=top align=left bgColor=#ecf2f1>Total tank level averaged = 65.2 litres</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>1_6.2</TD><TD vAlign=top align=left bgColor=#ecf2f1>0667</TD><TD vAlign=top align=left bgColor=#ecf2f1>Indicated value and tank phase.
1 = Both sensors OK. 2 = One sensor fault.3 = implausible input
</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 7: Temperature and speed</TD><TD vAlign=top align=left bgColor=#ecf2f1>7.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>032</TD><TD vAlign=top align=left bgColor=#ecf2f1>Coolant temperature input 32C (90F)</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>7.1</TD><TD vAlign=top align=left bgColor=#ecf2f1>245</TD><TD vAlign=top align=left bgColor=#ecf2f1>Outside temperature input 24.5C (76F)</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>7.2</TD><TD vAlign=top align=left bgColor=#ecf2f1>5283</TD><TD vAlign=top align=left bgColor=#ecf2f1>Engine speed 5,283 RPM</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>7.3</TD><TD vAlign=top align=left bgColor=#ecf2f1>085</TD><TD vAlign=top align=left bgColor=#ecf2f1>Vehicle speed 58 km/h (36 mph)</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 8: Input values in HEX code</TD><TD vAlign=top align=left bgColor=#ecf2f1>8.0-8.3</TD><TD vAlign=top align=left bgColor=#ecf2f1>XXX</TD><TD vAlign=top align=left bgColor=#ecf2f1>Hex code, instrument cluster inputs</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 9: battery voltage</TD><TD vAlign=top align=left bgColor=#ecf2f1>9.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>125</TD><TD vAlign=top align=left bgColor=#ecf2f1>12.5 Volts</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 10: Country coding</TD><TD vAlign=top align=left bgColor=#ecf2f1>10.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>02</TD><TD vAlign=top align=left bgColor=#ecf2f1>US 02</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 11: Cluster code</TD><TD vAlign=top align=left bgColor=#ecf2f1>11.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>000003</TD><TD vAlign=top align=left bgColor=#ecf2f1>Cluster code</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 12: Not used</TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1></TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 13: Gong test</TD><TD vAlign=top align=left bgColor=#ecf2f1>13.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>GONG</TD><TD vAlign=top align=left bgColor=#ecf2f1>Activate gong by pressing button (gong response is delayed)</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 14: Fault memory (not used for diagnosis)</TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1></TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 15 - 18: Not used</TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1></TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 19: Lock/unlock</TD><TD vAlign=top align=left bgColor=#ecf2f1>19.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>L-On L-Off</TD><TD vAlign=top align=left bgColor=#ecf2f1>Lock/unlock specific test functions</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 20: Average fuel consumption correction factor</TD><TD vAlign=top align=left bgColor=#ecf2f1>20.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>XXX9</TD><TD vAlign=top align=left bgColor=#ecf2f1>Press button when correct 1s position is attained</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>20.1</TD><TD vAlign=top align=left bgColor=#ecf2f1>XX5X</TD><TD vAlign=top align=left bgColor=#ecf2f1>Press button when correct 10s position is attained</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1></TD><TD vAlign=top align=left bgColor=#ecf2f1>20.2</TD><TD vAlign=top align=left bgColor=#ecf2f1>12XX</TD><TD vAlign=top align=left bgColor=#ecf2f1>Press button when correct 100s position is attained</TD></TR><TR><TD vAlign=top align=left bgColor=#ecf2f1>Test 21: Software reset</TD><TD vAlign=top align=left bgColor=#ecf2f1>21.0</TD><TD vAlign=top align=left bgColor=#ecf2f1>reset</TD><TD vAlign=top align=left bgColor=#ecf2f1>Reset software</TD></TR></TBODY></TABLE>Instrument cluster, self testing
Perform the following steps to access the instrument cluster self test functions:
  1. Remove and insert ignition key (ignition OFF)
  2. Press and hold RIGHT cluster button. “CHECK CONTROL OK” is displayed.
  3. Without releasing button, turn ignition switch to first dent (RADIO position). “TEST-NR. 01″ is displayed.
  4. Press LEFT cluster button for the test sub-menus.
  5. Press RIGHT cluster button to scroll to next test.
Note:
Test 1 and 2 are always unlocked
Test 3-21 are only accessible after unlocking using TEST-NR. 19 lock/unlock function. See Instrument cluster self test, unlocking.
Instrument cluster self test, unlocking
To unlock a specific test:
  1. Remove and insert ignition key (ignition OFF)
  2. Press and hold RIGHT cluster button. “CHECK CONTROL OK” is displayed.
  3. Without releasing button, turn ignition switch to first dent (RADIO position). “TEST-NR. 01″ is displayed.
  4. Use RIGHT cluster button to scroll to TEST-NR. 19 (lock/unlock)
  5. Press LEFT cluster button once to access TEST-NR. 19 submenu. “LOCK : ON” is displayed
  6. Use LEFT cluster button to scroll to test you wish to unlock.
  7. Press RIGHT cluster button once to unlock desired test. Display returns to TEST-NR. 01.
  8. Scroll to unlocked test using RIGHT cluster button.
  9. Press LEFT cluster button to perform desired test or access that tests submenu.
  10. Repeat unlock sequence for each test required.
  11. Switch ignition OFF to cancel self test mode.
Note: Display shows no visual confirmation of test unlock.
Instrument cluster, software reset
To reset instrument cluster software:
  1. Remove and insert ignition key (ignition OFF)
  2. Press and hold RIGHT cluster button. “CHECK CONTROL OK” is displayed.
  3. Without releasing button, turn ignition switch to first dent (RADIO position). “TEST-NR. 01″ is displayed.
  4. Use RIGHT cluster button to scroll to TEST-NR. 19 (lock/unlock)
  5. Press LEFT cluster button once to access TEST-NR. 19 submenu. “LOCK : ON” is displayed
  6. Use LEFT cluster button to scroll to TEST-NR. 21. “LOCK : 21″ is displayed
  7. Press Right cluster button to unlock TEST-NR. 21. Display returns to TEST-NR. 01.
  8. Use RIGHT cluster button to scroll to TEST-NR. 21.
  9. Use LEFT cluster button to access TEST-NT. 21 sub-menu. “REST ?” is displayed.
  10. Press LEFT cluster button again to perform reset.
  11. Switch ignition OFF to cancel self test mode.
Note: Display shows no visual confirmation of test unlock.

Thank you to KinMak for having posted this else where.


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Could it be possible that there's a difference between the nav and speedo speeds because of the up and down grades of the roads? The GPS probably doesn't know if you're going up a grade or down a grade, would that make it possible there's a difference in speed, along with the wearing down of the tires decreasing the outer circumference of the tires?
 

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Discussion Starter · #6 ·
Could it be possible that there's a difference between the nav and speedo speeds because of the up and down grades of the roads? The GPS probably doesn't know if you're going up a grade or down a grade, would that make it possible there's a difference in speed, along with the wearing down of the tires decreasing the outer circumference of the tires?
Good thought, but its a known fact the speedo is off. At least according to the wheels that are on your car, which are rather important in determining speed. And you are right, if the circumference of the wheel changes, it has more revs per mile and I have no idea if the wheel speed sensor adjusts for this.

Maybe I should try a wind speed gauge on top of the car :biggrinbounce:
 

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Discussion Starter · #7 ·
That speed in 7.3 must be a calculated item. I wonder if its using a pre-determined wheel revolutions per mile, that changes depending on the tires, etc. If it bases the number on a tire that we no longer use, that could cause an inaccuracy. Next, you have to wonder if it could be changed. The number that is in there would look like 788 or something to that effect give the standard tire sizes.

I wonder what the standard tire sizes are for european models?

Also, did you see that in speedo accuracy ratings, BMW was dead last!!!
 

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Discussion Starter · #8 ·

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Discussion Starter · #10 ·
The error is programmed into the cluster itself. Mine is a constant 3mph. The OBC "average speed" reading is dead on accurate when compared to GPS.

Nice - I just read that somewhere else also. I wonder if they are reading from two different sources (one from the tranny, one from the wheels?) or if there is a build in + function between the OBC and Speedo.

My guess is two different sources. You also had to convert from m/s to mph correct?
 

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Good information as I was expecting the standard "you can't" answer. At least maybe we have some new stuff to toss around. The Germans are smart people (in some ways), but no match for a determined car owner!

Anything they can design, we can re-design correctly because we are a determined bunch and not because we are necessarily smarter! This thread never goes away and remains one of the more irksome annoyances with the Bavarian offering!

Bill
 

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All VDO speedos have a "factor" (wheel revolutions per mile?) which is determined so the speedo matches the car speed based on its parameters.

We know BMW designs in some error for it to read high. If it has a constant percentage reading high (say 3%), I would expect a good VDO repair shop could change whatever the parameter the stock speedo uses and put the correct "factor". Or just go with the aftermarket add on, which seems a lot easier.
Regards,
Jerry
 

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All cars have a POSITIVE error. It has been written about here, before ... do a search.

It is to provide legal protection for the manufacturers, if someone gets a speeding ticket (so you can't say your speedo showed you going slower than clocked).

BMWs have had approximately a 3 mile error at slower speeds for 40 years. Actually, it is about 1 MPH at 20, 2 MPH at 40, 3 MPH at 60, 4 MPH at 80. You used to be able to have the AAA check it for you. I have seen higher errors and lower ones.

Buy larger diameter tires!

I have no problem deducting from 1 to 6 MPH at various speeds.

You shouldn't be staring at the speed while driving, anyway! If anything, you should be watching the tach.
 

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Nice - I just read that somewhere else also. I wonder if they are reading from two different sources (one from the tranny, one from the wheels?) or if there is a build in + function between the OBC and Speedo.

My guess is two different sources. You also had to convert from m/s to mph correct?

They use the same source, the GPS speed signal is redundant and for GPS use only. The OBC and Speedo use the ABS (wheel speed) sensors to get their speed signal.
 

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The fact (some say) that BMW has the worst accuracy in the industry says to me that they have gone too far. I doubt highly that if you were in an accident and you proved that the speedo read 3MPH LOW they would face a lawsuit. I do think that most people dislike the error between say 50-80 and if I could just pull the needle off and put it at say -5mph when standing still, it would still be off, but closer in that highway speed area where we all know how important it can be to be doing 8 over instead of 13 over. We all want to know when we are really at the "edge" and not see cars up our butts all the time!

It's weird, but the mind just does not like adding a few MPH to your displayed speed to determine your actual! It is just a paradigm I can't get used to. I would pay maybe 125 bucks to buy a pulse convertor that would take the pulses from the wheel speed indicator and modify it by some percentage less.
 

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BMWs have had approximately a 3 mile error at slower speeds for 40 years. Actually, it is about 1 MPH at 20, 2 MPH at 40, 3 MPH at 60, 4 MPH at 80. You used to be able to have the AAA check it for you. I have seen higher errors and lower ones.
Mine is also 5%
 

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Yeah....nice thought but no. GPS's work off of time. A GPS can tell your elevation and your speed by calculating the time it takes for the signal to come from the satelite to the GPS reciever.

Ryan

Could it be possible that there's a difference between the nav and speedo speeds because of the up and down grades of the roads? The GPS probably doesn't know if you're going up a grade or down a grade, would that make it possible there's a difference in speed, along with the wearing down of the tires decreasing the outer circumference of the tires?
 
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