Speedometer error
12-19-2004, 11:36 PM
#1
Burning Brakes
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Speedometer error
I have read the previous posts on the apparent speedometer error in the P-cars. Mine reads 53 when I'm doing 50mph. Can this be fixed by the dealer? I have a 04 C2. Thanks....
Dave
Dave
12-20-2004, 02:19 AM
#2
Three Wheelin'
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I'd be interested in this too, as I also have this apparent issue... Big6, do you have any performance modifications on your car or is it stock? I only ask because I was thinking this might be the reason, but I could be totally wrong..
12-20-2004, 11:30 AM
#4
Burning Brakes
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Hi Guys,
My car is a stock (so far) 04 C2 with 18" stock wheels. I thought I read a post some where that a software change could correct this. I'm not too concerned about the speedometer error but more so about the odometer error. If I drive 50 miles and the odometer shows 53 miles, that will shorten the warrantee by a significant amount.....
Dave
My car is a stock (so far) 04 C2 with 18" stock wheels. I thought I read a post some where that a software change could correct this. I'm not too concerned about the speedometer error but more so about the odometer error. If I drive 50 miles and the odometer shows 53 miles, that will shorten the warrantee by a significant amount.....
Dave
12-20-2004, 01:15 PM
#5
Track Day
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There've been many previous posts on both the odometer & speedometer error..Was told by Stevinson Porsche in Denver that Porsche feels that any error within 10% is acceptable and will not make adjustments.
12-20-2004, 02:44 PM
#6
Three Wheelin'
Most manufacturers have a built in error of several percent...as I remember reading BMWs seem to be the worst. The only thing that is not legal [at least here in the US] is for the speedometer to be reading below your actual speed, so I think most manufacturers build in a higher number....it should work OK for you--3MPH at 50 isn't that bad [plus when you show 80MPH you'll be going slower in actuality]...I'd take it for what it's worth and not worry about it--it could save you from a few tickets [or help you pay less if you do get one] 
my $.02
my $.02
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12-20-2004, 03:42 PM
#8
Race Car
I have done numerious tests of my car, including several measured miles, and the odometer is exact at all speeds. I regularly travel to a place 123 miles away and have done so it 5 different cars and they all report the same mileage withing 1/2 mile.
12-21-2004, 01:43 AM
#13
Rennlist Member
I placed a high end Garmin GPS on my dash and at almost every speed there was a 3 to 4 mph difference in reading. My 99 996 C2 with 17's read 3 -4 miles slower than the GPS was registering.
Porsche considers this well within their margin of acceptable tolerance and that the speedo is an "approximation" of speed only IOW, Porsche considers this normal and it isn't an issue they are considering the issuance of a technical bulletin.
I also heard, though, I don't know how accurate this might be, but that they purposely gang adjust their units to read slow so that there is less liklihood of speeding tickets---again, I don't know if this is even remotely true.
Jim
Porsche considers this well within their margin of acceptable tolerance and that the speedo is an "approximation" of speed only IOW, Porsche considers this normal and it isn't an issue they are considering the issuance of a technical bulletin.
I also heard, though, I don't know how accurate this might be, but that they purposely gang adjust their units to read slow so that there is less liklihood of speeding tickets---again, I don't know if this is even remotely true.
Jim
12-21-2004, 10:34 AM
#14
The odometer is correct it is the speedometer that has a 2-3 mph offset. Notice I said offset not error. This is built in on purpose. For what purpose I don't know. The Germans have there reasons but so far have not told us. My Toyota is right on. Again I believe this is also on purpose.