The A3 stands sporadically circulating

Good morning, we have an A3 Sportback TDI 1.9 of 2006 8PAAJ4 with BKC engine and GQQ gearbox, with a problem that has us crazy. Circulating stops sporadically and then it does not start. The vehicle records the faults: 17909 P 1501 Relay for fuel pump J 17 Short to mass and 19794 P 338 UC Preheating cycle 1 activation. Breakdown in the electrical circuit. Sporadic. At the time of the failure we have battery voltage in SB 27 and SB 15 but we do not have battery voltage in the fuel pump (G6) at that time of the check, after a few seconds it has battery voltage again in the pump (G6). We have replaced the J17 the J 179, fuel pump, UC Motor, Ebox box. The electrical installation from the UC Motor to the J17, to the J179, from the J17 to the fuel pump, feeds, masses and everything is correct. We have assured the correct state of wiring and pineado from relay J17 to UC J179 and the SB15 fuse. We carry out parallel installation from the J17 relay to the UC J179. The electrical installation has been thoroughly reviewed and the failure has been reproduced again. We request help. Thank you so much. Greetings

Check your crankshaft position sensor, if this fault kills the pump signal, spark plugs, etc., ESEPRO serves you.

Greetings

I will, but I do not fit that I record those electricity breakdowns and the fuel pump does not sound or send. Greetings and thanks

Change the fuel pump relay

It may be after warming up, the relaxation stopped
fencing - reflective fuel pump
- fuel pump relay is open or shortly
I would exchange it.