Speedometer Parameters (E67)

[Admiral Ballsy]

Apologies if this has been covered, but I was unable to find anything directly answering my question via search.

What pieces of data in the following table are actually relevant?

14190

This is the factory data. The first thing that leaps out at me is the H0139; 2540 is way too large. The tires are 225/60-17, which are actually around 2200mm.

The H0136 number is more accurate; 496 rev/km works out to 2016mm circumference. In any case, the speedometer is pretty much accurate.

But it's obvious that both of those values can't be right, they are contradictory. So at least one of them must be ignored. Are these 'real' values in the ECM, or are they calculated by EFIlive for presentation from other data?

[Blacky]

There are a gazzillion speedometer related parameters in the GM ECMs. They can be configured in an almost unlimited combination. Some values are used some are not, some values cause other values to be ignored, some values affect the internal speed that the ECM uses to compute things like gear changes, some values control the dashboard speedo gauge, its a real mess.

The thing to do when attempting to figure out what you need to change for your particular configuration is to change only one parameter at a time. Data log the results and make sure the VSS PID is displaying the same value as your vehicle's dashboard gauge. If not, then you've changed a parameter that controls one but not the other.

Regards
Paul

[Admiral Ballsy]

Thank you!

[Blacky]

Are these 'real' values in the ECM, or are they calculated by EFIlive for presentation from other data?

I forgot to add, they are all real calibrations in the ECM and none of them are calculated or computed by the EFILive software.

Regards
Paul