A4 Avant - Transfer Fuel Pump Question

[Wayne33]

I own a B8 A4 Avant with a 2.0T engine and about 110K miles. A couple weeks ago the check engine light came on and so I went to the dealership. They said the code is for a "G6-Transfer Fuel Pump (FP)." Odd thing is the next week the light went off and then the following week it came back on. This morning the car started a little rough and the check engine light started to blink. I shut off the car, then started it back up and the check engine light came on but no blink. I drove the car around and it worked fine from then on. As I was driving the car back home the light actually went off again!

Question: Is the fuel pump a common problem for the B8 platform? Why would the check engine light be intermittent if it's a fuel pump issue?

Any context for this issue would be super!

[Smac770]

The pump itself, I don't think so. But the controller for it I think can overheat. As for intermittent, anything can be intermittent. My P0299 would come and go, now it's always on. My right rear door lock actuator would often not unlock for several months. It's working fine these days. I'd be curious what the complete DTC message was. "some problem of some nature with something related to the in-tank pump some times" is not particularly informative. MIL light blinking means excessive misfires, such as poor fuel delivery. You should have likely had more DTCs than just something for the G6 pump.

[Wayne33]

Thanks for your reply Smac770. I dropped the car off this morning to find out what's going on. I know there's both a high pressure fuel pump and a low pressure fuel pump - I'm wondering if the issue is related to one or both. I'll loop back when I get the diagnosis.

[ps2cho]

The fuel tank likely has two connected but separate chambers as it’s split to bend around the driveshaft. The transfer pump ensures both sides have fuel in it for cornering. The pump may be getting weak and is unable to ensure equivalent volume in both sides.

[Wayne33]

To follow up, the issue was a bad low fuel pressure pump (P310B). The dealer replace it and the fuel filter ($) as well as a fuel line (no charge). The low pressure fuel pump was at a 78% duty cycle which is high. The car runs a lot smoother now and the throttle response is better.