[ironduke2010]

I pulled a 3792 code today via Carly (log below), which wasn't there about a month ago. I had been diagnosing a loss of power issue before the code finally showed up (and had changed the coils, plugs, and a temperature sensor) but now that the code is thrown, it's obviously the place to focus.

This pdf (http://www.n54tech.com/flash_files/N55_codes.pdf) has 3792 as "Coolant pump, speed deviation: outside tolerance"

possible fault causes are:
- Air in the cooling system
- Defect in wiring harness to water pump
- Defective water pump

Going from smallest to largest, I started with "Air in the cooling system", and did the well documented self bleed process. While I could confirm that the water pump was indeed pumping by seeing the coolant circulate in the expansion tank, the process ran for over 20 minutes without completing. All the guides say it should complete in 12 minutes. I finally stopped it by powering down the car.

1. Is the fact that I saw coolant circulating sufficient to conclude the water pump is good? Or could it just mean it wasn't having problems at the time?
2. Is the self bleed process supposed to somehow sense there is no air in the system before it terminates? Or is it more of a timed run?

There were no other codes (so far). Does code 3792 pretty much mean I will need to replace the water pump (and thermostat) eventually? If so, so be it, I just want to go through the due diligence of eliminating other possible sources.

The temps via dashboard gauge have been pretty normal throughout. My car has always operated at about 230-250F, including the periods when (presumably) the 3792 code was thrown.

Car is a 2011 335 xdrive e92 with about 88k miles, and, a few months out of CPO...

Log details from Carly below. I can't say I totally understand them, including the mileage info, or where it pulls it's info.


> Found Faults:
> --Engine / Motor--
> *** 3792:Engine cooling system: speed coolant pump out of tolerance ***
> Fault-Set 1 - ( 87931 mi)
>
> battery voltage: 50.43 V
> Coolant temperature OBD: 71.15 °F
> number of revolutions: 0.00 rpm
> Water pump speed: 0.00 -
>
> Fault-Set 2 - ( 954 mi)
>
> battery voltage: 16.13 V
> Coolant temperature OBD: 145.40 °F
> number of revolutions: 0.00 rpm
> Water pump speed: 69.00 -
>
> Fault-Set 3 - ( 447 mi)
>
> battery voltage: 48.13 V
> Coolant temperature OBD: 212.90 °F
> number of revolutions: 0.00 rpm
> Water pump speed: 0.00 -
>
> Fault-Set 4 - ( 740 mi)
>
> battery voltage: 20.22 V
> Coolant temperature OBD: 64.40 °F
> number of revolutions: 4416.00 rpm
> Water pump speed: 0.00 -
>
> Fault-Set 5 - ( 974 mi)
>
> battery voltage: 37.89 V
> Coolant temperature OBD: 191.30 °F
> number of revolutions: 0.00 rpm
> Water pump speed: 0.00 -