[Eternalthinker]

I drove my daughter's X5 45E for the week she came home for the Holidays and noticed that from time to time in EV mode there is insufficient power to go uphill at 65-70mph. It is not consistently the same, but it happened enough to make me wonder if there is an issue with the EV motor. The system switches the engine on to run on ICE, but it doesn't always do that on this incline.

Any thoughts?

[typedcl]

When you say insufficient power, does the car slowly lose speed? How far uphill at what grade?

You description sounds like what my 45e would do.

On big downhills, I've see it stay in electric mode 80+ mph.

[eelnoraa]

I think it is normal. Heavy car, low HP motor, uphill, so HP not only need to over come drag and fiction, but the a portion of weight is the car (depend on the grade).

[Eternalthinker]

Originally Posted by typedcl

When you say insufficient power, does the car slowly lose speed? How far uphill at what grade?

You description sounds like what my 45e would do.

On big downhills, I've see it stay in electric mode 80+ mph.

It is on a 6% grade and would lose speed going from 65mph to about 55mph and maintain from there. There is also a Drivetrain malfunction light that turns on when this happens.

[typedcl]

Originally Posted by Eternalthinker

There is also a Drivetrain malfunction light that turns on when this happens.

I would take it to the shop if there is an indicator light.

My car can slow down since the electric motor isn't strong enough for some uphills... but it never displays anything. If I'm in hybrid mode, the engine will usually start if the accelerator is pressed far enough. Not past kickdown, maybe halfway is good enough.

[Eternalthinker]

Originally Posted by typedcl

I would take it to the shop if there is an indicator light.

My car can slow down since the electric motor isn't strong enough for some uphills... but it never displays anything. If I'm in hybrid mode, the engine will usually start if the accelerator is pressed far enough. Not past kickdown, maybe halfway is good enough.

Dropped off for service and preliminary diagnostic is that there is a "surge" that caused the drivetrain light to turn on. The code was sent to BMW for further guidance. Will post about results when they hear more.