Quote:
Originally Posted by MetroMPG
Is it just the odometer, or the speedometer too?
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FWIW, the local speedometer shop (which also calibrates the Arizona Highway Patrol vehicles) states that on GM veicles the ECM data is ≈100% accurate to the odometer, but is automatically artificially *incremented* by +2 mph -- by the ECM -- to the speedometer.
So, the odometer is purposely MORE accurate than the speedometer.
And, I *see* that ≈+2 mph offset on my SGII on both 2004 & 2009 Pontiac Vibes, 2011 Chebby Cruze, and newest 2014 Prius. So, it looks *universal* to me.