Pressure sensing glow plug position? Q5 2014 TDI

After running tank the lowest it's ever been(wife), I got a glow plug light. Was off after re-start. It came back on yesterday but, again, didn't reappear after a restart. On the way to work, wife tells me glow plug and cel. I've already read where it could be, plugs, fuel pump, fp controller, fuel filter, HP fuel pump(with entire fuel system).

IF, it's the glow plugs, I read these engines(CPNB) use 5 regular glow plugs and one pressure sensing one. If this is correct, is it always in the same position? IE: Cylinder 1 or 4, etc.?

I'm going to see what VCDS reveals after work.

The dieselgate fix swapped out one of the glow plugs for one with an added O2 sensor. The circumstances suggest a fuel line issue though.

Thanks, Myth. VCDS confirmed the worst. Low high pressure rail. I've only got 64K miles. I'm waiting on a call from my local dealer.

It may well be the intank lift pump failing. The only codes it will show when that happens is low high rail pressure. When I replaced mine, it was a new part number.