Quote:
Originally Posted by kaiser
Maybe the poster should make sure what the situation really is.
Many Rovers over read by about 5 to 7 per cent on speed.
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It is actually a very precise amount of over read on all cars, derived from the O/S ABS sensor, then fed into the IPK. The IPK then adds a precise +% so as to deliberately over read. The only possible small variations are in tyre size (upto 1mph), or much less likely (because an ABS fault would appear) as fault in the ABS sensor.
There is not as yet a known fix for it, other than getting the IPK with matrix display, reprogrammed by a T4 guru to show the correct speed data in the display. The IPK is fed accurate data, only the analogue speedo is tweaked in software to show the +5% - everything else is fed with correct speed data.
Your GPS can be relied upon to be accurate on a reasonably straight and level road, where you have good reception.