What do these codes actually mean?

[hefy_jefy]

I am currently trying to figure out if I need to fix a problem.  I just had an engine trouble light (the first time I have seen in 50,000 miles) on my 2014 R1200RTW - the fault code was:

21F520 : Electric fuel pump, short circuit to ground
Currently present : NO
Engine warning light (MIL) : NO
Frequency count : 1
Logistic(Healing) count : 39
.Fault Code History :
...Record number : 1
...Odometer : 50516.7 mls
...ABS time : 5360160
...Engine speed : 0.0 rpm
...Vehicle speed : 1.2 mls/h
...Battery voltage : 11.91 V
...Electric fuel pump voltage : 11.23 V

Its now cleared and all seems well, (I ran the fuel pump test, very handy) however I am about to head up to Alaska and I really don't want to get stuck and eaten by bears.
I could simply replace the fuel pump, but then this fault description seems odd, the tank and almost everything around it is plastic so a "short circuit to ground" is unlikely to be the pump, it could be a chafed wire somewhere upstream of the pump.  Looking at other posts I have gleaned that there are (at least) the following additional codes associated with the fuel pump.

21F5E0 : Fuse activated for Electric fuel pump, short circuit to ground or overload
21F522 : Electric fuel pump, open circuit

Both of which would certainly point to the pump, and replacing it would be obvious. I suppose it could also be a "glitch" but why after 50,000 miles?

So my question is - who actually decides what the description of fault 21F520 is?  Presumably BMW Motorrad have a very precise description in German, I assume HEX Code Za have this, if so who translates it? Somewhere buried in the GS-911 code there must be a lookup table that generates a human readable text string that corresponds to each code.

Of course there is no list online (I have looked) for these codes, but somebody must know.

...I will probably just change out the pump, but I am not filled with confidence that this will be the solution.

If I get eaten by bears I will have someone let you all know.

Geoff 

[WayneC]

The output driver IC in the ECU detects over current or under current and sets an error flag to the ECU processor the processor then generates the fault code which is made up of ECU Address, sub component address & fault condition, short circuit to ground means higher current than within the range expected

[hefy_jefy]

Wayne - thank you, this does make sense, my feeling is that this was probably a "one-off" fault since it has not occurred since, I have run the fuel pump test several times and checked the current draw, it seems reasonable and consistent at about 4 amps.

Looking at the circuit diagram there's also an electronic switch between the line between the pump and the ECU so I guess this could also have a problem, but less likely since its solid state.

Geoff

[WayneC]

You will find that fuel pump controller has had failures, there is discussion about it over at Advrider forum, perhaps a spare for the Alaska trip ?

[panason1c]

Battery voltage : 11.91 V

Isn't the battery voltage too low?

[hefy_jefy]

Good point, when I was checking the current drawn by the pump I noticed that the 4.5 amp draw was enough to make the battery voltage droop an bit with the engine off, I wonder if this could cause the error.  In the past I have noted that strange things can happen if the battery voltage goes south...

And yes on the controller, but the Adventure rider guys are on the GS where the fuel pump and electronic controller are on the outside and exposed to the elements a bit, on the RT its buried away under the tank and should be better protected.
 
Geoff

[hefy_jefy]

Just to close this off I am back from Alaska (great ride!) and no problems with the fuel pump.  I just checked with the GS-911 again and indeed the fault has gone, "healed itself" - good information from WayneC.  So despite all the dire warnings from various BMW mechanics this must indeed have been a glitch - possibly caused by the low battery voltage?

The only question is if the bike is still under warranty (it is), a fault like this shows up and all the BMW advice is "change out the pump" (god knows what the bill for that would be) they should do it under warranty?  haha!  good luck with that...

Needless to say I didn't get eaten by bears...
Geoff

[WayneC]

Pleased to hear you had a good trip and were not eaten by bears, yes you should refer it to the Dealer for possible warranty replacement