B8.5 - EPC light, Fuel pump code, pump morse code, runs fine

[Stereodude]

My 2013 S4 with 135k miles has been getting an intermittent EPC light over the past week or so. No CEL. It doesn't come on immediately after starting the car. The car runs and drives fine. The code comes up as:

11010 - Fuel Pump
P3043 00 [175] - Mechanical Malfunction
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 7
Mileage: 217432 km
Date: 2024.10.10
Time: 13:35:27

I scanned the car two different times after getting the code and the frequency increases.

Muting the radio and sitting at idle the pump sounds like it is speaking Morse code with a sort of choppy pulsing sound like it is maybe turning on and off rapidly but inconsistently or changing pump RPM in the same way. It seems to do the same thing when driving, but it gets lost among the exhaust and road noise. I tried to get a video, but the phone's mic wouldn't pick up the sound well.

Is there any easy way to know for sure if it's a bad pump or the control module for the pump before I start buying parts? Or is the code definitive to the pump?

[LowKeyLoki]

It is almost 100% the pump failing, considering the fact that you are at 135k miles you are overdue for a new pump. If you can audibly hear the pump malfunctioning then that is your best sign. Go ahead and replace it for the peace of mind so you don’t get stranded when it does finally go.

[Stereodude]

It is almost 100% the pump failing, considering the fact that you are at 135k miles you are overdue for a new pump. If you can audibly hear the pump malfunctioning then that is your best sign. Go ahead and replace it for the peace of mind so you don’t get stranded when it does finally go.
Thanks for the reply. I've ordered a VDO/Continental pump assembly. Do I really need this cap though?

https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/cap/8r0201263a/

I didn't see it in any of the YouTube videos I watched that showed replacing the pump.

[LowKeyLoki]

Unless you have the tool to get it off you will almost break the cap especially if you use a chisel. Which you shouldn’t use a chisel, if you do it needs to be brass to avoid sparks. oEM tools makes a fuel tank cap tool for like 20$ on Amazon and is worth the money but still buy the new lock ring as they are fragile. And get new seat clips as they will break as well.
As for that cap on the fuel pump yes you should replace that as well.

[Stereodude]

Unless you have the tool to get it off you will almost break the cap especially if you use a chisel. Which you shouldn’t use a chisel, if you do it needs to be brass to avoid sparks. oEM tools makes a fuel tank cap tool for like 20$ on Amazon and is worth the money but still buy the new lock ring as they are fragile. And get new seat clips as they will break as well.
As for that cap on the fuel pump yes you should replace that as well.
I think you are calling the large white plastic lock ring the cap. I was asking about the little black cap (https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/cap/8r0201263a/) that I found references to supposedly needing. I pulled the seat yesterday (broke the seat clips in the process) and removed the metal cover to look for the little black cap but I didn't see that it anywhere. I saw 3 connectors to the top of the pump housing.

I ordered a new white plastic lock ring, gasket, seat clips, and pump assembly. I should have all the pieces tomorrow.

Are you referring to this tool? https://www.amazon.com/OEMTOOLS-25156-Module-Spanner-Wrench/dp/B004FDL3BS/

[LowKeyLoki]

Yeah that is the tool to get the lock ring off.

[Stereodude]

If you buy the Continental/VDO pump, part number: A2C53395208Z, you need a female 1/4" SAE J2044 end cap/plug. The factory Audi pump has the male port plugged on the inside, but the Continental pump doesn't. Hence the need for the plug.

BTW, Rock Auto has the Continental pump for $309 + tax & shipping. You'll have to search for the part number though. It doesn't show up under fuel pump listings listed for the car.