Originally Posted by SRT6_Roadster
The ECU limits the number of revs allowed at a stand still for self preservation and engine longevity.
Neither the C32 guys nor the SLK32 guys have issues dynoing their car. Not sure what the deal is with the crossfire.
Its the Crossfire ECU that has some extra 'rationality' checks on the various systems in the car. As well as just looking for open and short circuit sensors it checks to see that the sensor signals are appropriate to the conditions based on the state of other systems in the car. The CAB (Controller Anti-lock Brakes) constantly checks the differential between the front and rear wheel sensors and imposes a 5,000 rpm limit if the fronts are stationary in relation to the rears. Its actually even more complicated than that as it ties in with some of the emission systems too, but that's another story.
The SLK's have a 'dyno' mode that can be set via the multimode dash display (which we don't have) that disables this CAB 'feature' until the ignition is cycled.