HVAC Fault code E729 - K-CAN failure

[PHL08]

While diagnosing another problem, my Carly reader revealed that my HVAC system is giving a K-CAN fault code E729. Not sure where the best place to start investigating this one. Suggestions? 2008 E70.

[ard]

battery fully charged?

Clear the code, it comes back??

Any other symptoms???

[PHL08]

Yes battery full, and code cleared but immediately returns. No other symptoms I can think of. It randomly came on a week ago and hasn't gone away.

[PHL08]

<deleted>

[Dieseldonkey]

I've had same intermittent code as well
Subscribing...

[Westlotorn]

My wife took our 2008 X5 to the car wash yesterday, the car had been sitting for a couple weeks so the battery was probably low, AGM battery. Started and drove fine to the car wash, started and drove into the car wash. After the wash they shut it off while drying and cleaning the interior. Would not start after this. Engine seemed to turn over fine but would not start. I took my car trailer over to pick it up, not looking forward to dragging it on the trailer with the car locked in Park. Stupid BMW Feature in my opinion. Who wants to climb under a car and turn an unlock bolt to put a car in park if the engine won't run. Sorry, my rant. Get the trailer in place and hook up the cable to drag the car on and I ask my wife to try to start once more. It fires right up like brand new? Drove it home and I hooked up my battery charger at 25 amps, AGM battery, it charged for a few hours so it was very low. After all this I scan the system, several low battery codes cleared right away for me. The E723 code pops up and will not clear, says no communication to the sensor. It was 109 degrees when it broke down yesterday at the car wash. Tested the fuel pump several times it seems quiet and smooth. No idea why it did not start unless the battery was low enough to spin the engine but not wake up other modules and then why suddenly this E723 code that will not clear? Appreciate any advice.
Car is at 124,000 miles and has been serviced best I can over its life.
Mark

[deepblonde]

Originally Posted by Westlotorn

My wife took our 2008 X5 to the car wash yesterday, the car had been sitting for a couple weeks so the battery was probably low, AGM battery. Started and drove fine to the car wash, started and drove into the car wash. After the wash they shut it off while drying and cleaning the interior. Would not start after this. Engine seemed to turn over fine but would not start. I took my car trailer over to pick it up, not looking forward to dragging it on the trailer with the car locked in Park. Stupid BMW Feature in my opinion. Who wants to climb under a car and turn an unlock bolt to put a car in park if the engine won't run. Sorry, my rant. Get the trailer in place and hook up the cable to drag the car on and I ask my wife to try to start once more. It fires right up like brand new? Drove it home and I hooked up my battery charger at 25 amps, AGM battery, it charged for a few hours so it was very low. After all this I scan the system, several low battery codes cleared right away for me. The E723 code pops up and will not clear, says no communication to the sensor. It was 109 degrees when it broke down yesterday at the car wash. Tested the fuel pump several times it seems quiet and smooth. No idea why it did not start unless the battery was low enough to spin the engine but not wake up other modules and then why suddenly this E723 code that will not clear? Appreciate any advice.
Car is at 124,000 miles and has been serviced best I can over its life.
Mark

Any update or solution to this E723 code?