Pre64

Reading thru previous posts regarding speedo errors of from 2-5 mph - shouldn't the greater concern be the inflated odometer error as well as the miles per gallon assumptions. Our gas mileage, tire mileage, service mileage, and our cars aren't doing as well as we think. "5" miles lost for every 60 we think we've driven is huge!

Bob in NY

my bmw has the same problem, 3 to 5mph off but the dealer claims it's within spec. The bmw digital read out is correct and analog is slow. On my Porsche, the analog and digital are the same but I went by one of those radar signs that displays your speed, it showed 3mph slower than the speedo. Gues the German's are protecting us from ourselves...

Itzkirb

So when I'm going 178mph i'm actually only going 175mph? That really sucks...hahaha

redcab

Worn down tires (reduced circumferance) also will lead to slightly "faster than your really going" readings and "shorter than you've really travelled" measurements.

penguinking

well...its not going to be 3mph all the time. its going to be a proportional difference. so 3mph slower at 25, but it may be like 10mph difference when you're going 130. and that is a big difference

krisd

My actual is about 4mph slower than the speedo (both digital and analog) between 40 and 90 mph on the speedo. This was based on my GPS readings. I have also timed the speed on some of those test zones with the mileage markers and that was also showing a 4 mph difference. I have really not paid attention to the differences below 40 mph. Based on this I would guess the difference is pretty consistent throughout the entire range. If you figure you average 65 mph then you would have 616 miles less than actual every 10,000 miles. That is quite a difference. Good news is that gives you a 923 mile cushion for your 15,000 mile oil change. My other two cars (Acura and Yukon) are both dead on at 70 mph.

krisd

I believe most member here hit the time limit before the mileage limit on the warranty, but wouldn't it such to have a major problem at 1,500 out of warranty? You could probably have an interesting discussion with the service manager regarding that one!

penguinking

https://rennlist.com/forums/showthre...ometer+reading

old thread but some info we might have been missing out on

Gnome

I talked to the dealer about this a while ago. They confirmed that speedo reads fast, but said the odometer does NOT have a corresponding error. I have not checked scientifically, but rough comparisons to my wife's car suggest that the odometer is correct (well, matches my wife's car, at least).

penguinking

just to recap - so is there a fix for this speedo error?

chitownbob

I am also interested in any odo glitch because of warranty concerns. I don't want my 75,k warranty runnout out 5-6 k miles early!!!!

Bobby

Moogle

theres no 'fix' its just how it works.

the odometer still works normally.

SteveFromMN

The offset is just that an offset it does not change with speed. This is built in for some stange German reason. It can be reduced from a 4 mph offset to 2 mph offset with a programming change at your dealer. At least this was possible in 1999 I don't know about other years.

penguinking

i dunno...i just dont want to be misleading people when i talk about my top speeds, or when i tell people my exit speed at a corner - cause if my speedo reads 120 when its really 115, it affects my perception of speed and thats the real problem.

Pre64

Just completed a 1,000 mile trip & check of odometer vs. GPS. My '99 Coupe speedo (both digital & analog) vary from the GPS by @4 MPH. AND the odometer readings (digital vs GPS) refected the same issue. The mileage difference was 44 MORE miles registered on the car vs. GPS trip log of moving mileage. Humm - let's see that's about 4,400 per 100K miles!