I observed something strange about the range indicator in my TLX. It tends to jump up and down wildly depending on what happened in the previous few minutes of driving. For example, in my morning drive to work today, it varied from 440 to 660, back to 450, and then back to 650 - all in about 20 miles. What's more, it doesn't just continuously respond as a function of the recent fuel consumption data. Instead, it goes through long periods of reasonable stability, to sudden jumps by 100-200 miles up or down in a matter of a minute. This seems like a very strange behavior. It would be much more reasonable to project the range based on historic mpg data, at least starting from the last fill-up, and this would actually produce a slowly-varying and useful indication. As it is, the range indication is practically random, and can only be mildly useful when the fuel is almost gone, and the variations are largely reduced. Is it one of those software bugs that need to be fixed?

 

This is the first time that this has been reported/observed. It may be that the calculation are weighted to the most recent mpg experience. Highly unlikely that there will be a software change.

 

I think i read that these calculations are based on the x last minutes of driving. So if you get caught in traffic for a couple miles it will drop down significantly and then when you get on a highway it's gonna jump back up.

 

That's what its supposed to do.

If you are flogging your engine for a few minutes, idling, or stuck in traffic, the range will drop since the car is predicting your future usage based on current usage.

On the flip side, even if you are really low on gas, and start babying the engine, you will find your range may stop dropping, or even go up as you are driving.


Sounds like your trip meter is set to reset for each drive. I changed my trip A to reset at fillup, and trip B to only reset manually. Options for all 3 are in the MID.

 

So yes, it appears that the range meter is sensitive to whatever happened in the last few minutes of driving. In other words, the system assumes that my driving style in the next 5-10 hours of driving, distributed over 1-2 weeks, will exactly repeat whatever I was doing over the last few minutes. But does it really make any sense? Suppose I fill up the car in the beginning of a road trip and I want to plan when to look for the next gas station. If I am in the middle of a downhill section of a road at the moment, I will get an unrealistically high range estimate, which will never materialize. On the contrary, if I am stuck in traffic for a few minutes, the range will probably drop close to zero. Both of these situations are not well suited for trip planning. It would make more sense to use a more statistically-averaged estimate that follows long-term trends and changes very gradually.

 

You will need to get used to it working this way. It has been like this for the last 3 generations of TL, and I think you will find that it averages out quite well.