Anyone able to tell me what's the difference between a Rough Road and a Smooth Road spec vehicle? In regards to the PCM?

Backstory:

I got a P2135 on my UK-spec X350 XJR this morning.

After reading the Service Action K040 I decided to reflash my PCM.

The file shown during programming is "N19 - 4.2L SC Smooth Road" which makes sense given it's a UK-spec vehicle.

But it's been imported to Australia....soooo....

I'm just wondering, what's the real difference between a Rough Road and a Smooth Road spec vehicle?

Australia is in the Rough Road category...

 

Anybody?

 

Wow, new one on me. Hard to see UK roads as smooth

 

Maybe higher ride height?

Which would be exactly what you don't want given your earlier exercises.

 

I don't think there's any difference in ride-height, the specs list only one height.

Maybe something to do with the climate, rather than the roads, the countries in the rough road list are hot, and or tropical. Maybe also something to do with the quality of fuel available?

I don't know, which is why i'm asking.

The thing is there have been a number of TSB's which are referring to rough road markets only, or some particularly hot countries (i'm specifically talking about issues related to the TPS) for example the Service Action posted in the OP.

There was also a mention (somewhere, can't find it right now) that the signals from the TPS were getting mixed up "under certain conditions" and that the reflash helped solve this.

I'm really curious as to what the differences in the ECU could be, to justify having different files...

 

Pity we can't get the source code!

 

Rough Road vs Smooth Road.....

Question pops up during reconfiguring the ECM. It selects the configuration values for misfire detection. Rough road countries, i.e. Saudi Arabia, Iraq and some African Continent countries don't know what a smooth road is. Misfires are detected by detecting small crankshaft acceleration changes [or lack thereof]. If there is a misfire, the power stroke acceleration of the crankshaft is missing for that cylinder; equals misfire cylinder X.
Well, on extremely rough roads, the jarring can actually flex the crank and these changes can be detected by the crank sensor. Rough Road programming desensitizes misfire detection, to prevent false Check Eng lights for misfires that aren't there.

Sorry, just isn't a one sentence answer for that one.

Cheers,