CLS - Mpg / trip computer question

[gordonsood]

Hello. I am new this froum and came across it while trying to google my problem. Hopefully someone can assist me.

A few days ago I traded in my 2010 e220 coupe for a 2012 cls 350. I took the car for a long drive yesterday and noticed that the mpg was not updateing to the point after 44.1mpg from start. It would always jump so next one was 44.8 then it would jump in 0.7 or 0.8 increments. I noticed the mpg from reset was good and working in 0.1 increments as it should do.


Is this normal is my question? Am not getting a accurate figure. It works ok for reset and it worked ok in my older e220. Is this a issue I need to get looked at or is this how they have done it in the cls?

 

[HumberMart]

My 2013 behaves the same. It has also worked in similar increments on other Mercs I've had.

 

[gordonsood]

ah. thats pretty disapointing. esp when the reset one works fine.

 

[HumberMart]

The truth is that even if it did work in tenth increments it would be of little value as the accuracy is less than one mpg.

I suspect that the feature may occur due to conversion from km per litre, but I'm sure there are others on here that will know the real reason.

 

[whitenemesis]

Have you compared the reading with brim-to-brim manual calculations?

Personally not sure of the relevance of a 0.1mpg resolution.

 

[artyman]

Both mileage registers move in 0.1 increments on my W204, though it doesn't relate to the actual mileage achieved.

 

[HumberMart]

Have you compared the reading with brim-to-brim manual calculations? Personally not sure of the relevance of a 0.1mpg resolution.

From my experience, MB fuel computers are more accurate than most. I usually find they over read by no more than 2 mpg or are within 5%.

I've found VAG group cars to be a bit more optimistic. A TT I had over estimated by nearer 10%.

 

[whitenemesis]

From my experience, MB fuel computers are more accurate than most. I usually find they over read by no more than 2 mpg or are within 5%.

I've found VAG group cars to be a bit more optimistic. A TT I had over estimated by nearer 10%.

Indeed both mine read very close to actual. But I don't feel the need for them to measure to a resolution of 0.1mpg.

 

[ScotCLS]

I have found mine to be fairly inaccurate, if it says 38 it'll brim at 36 if it says 44 it might only be about 39-40.

 

[gordonsood]

i just done another long drive and once it hit 40mpg from start it started to jump again and not go up in 0.1

i think this has to be a computer glitch as my old e220 was perfect. also my info from reset was showing ----mpg so its not holding data there.

i think i will book it in for a check. maybe it needs a software update. i will update here once i speak to the dealer

 

[dan-mb]

i just done another long drive and once it hit 40mpg from start it started to jump again and not go up in 0.1

i think this has to be a computer glitch as my old e220 was perfect. also my info from reset was showing ----mpg so its not holding data there.

i think i will book it in for a check. maybe it needs a software update. i will update here once i speak to the dealer

Was the engine running when it said ----mpg, Mine only shows that if the engine is off. Perhaps the large jumps are accurate as the engine was warming up, hills, driving conditions...would explain why it was then going up in 0.1's with steady driving.

 

[gordonsood]

just to update i spoke to MB today and they advised that the computer should not behave as it is and be more like my old e class.

they booked the car in for a warranty repair next week. i will update you once its been repaired and and i also have a meeting the following day which will require a long drive so i will be able to test it

 

[gordonsood]

Was the engine running when it said ----mpg, Mine only shows that if the engine is off. Perhaps the large jumps are accurate as the engine was warming up, hills, driving conditions...would explain why it was then going up in 0.1's with steady driving.

yes your rite about driving conditions but i would expect that when you just get in the xcar and maybe for the first 5-10 miles. not after 100miles on the motorway.

the from reset i have not seen if it shows anything when cars off. it should be on there constantly

 

[dan-mb]

sorry i miss read your previous comment.
My "current mpg" goes to ---- with the engine off. But my "after reset mpg distance" is still on the dash screen.