Audi A3 TDI glow plug light flashing. Turbo doesn't kick in. Persistent problem now. Previously, it came and went.

SOURCE: my golf gt tdi glow plug light keeps flashing

check to see if your brake lights are working.usually the stop light switch fails and is the cause.but before buying a new one check the stop light fuse.its a common problem with a simple fix.hope this helps.

SOURCE: audi a3 tdi 140 turbo sounds like its whistling

Turbo vehicles often sound like they are whistling when the turbo spools up because it is sucking in air at a high rate and it makes a bit of a whistling sound. Generally not a problem unless it is a different whistling that you are referring to.

SOURCE: Audi A6 3.0 tdi Quattro 2005, glow plug light comes on, limp mode

16619 -Engine boost condition - Limit not reached. Check intake hoses/ connections for leaks. Check Turbo charger waste gate regulating valve/ waste gate working correctly. Must move freely when accelerating, won't achieve full boost if waste gate sticking open. Check Turbo impeller turning freely, oil feed pipe for turbo can get blocked causing impeller to seize. Engine compact, not easy to access these components.

SOURCE: how to change a turbo

YOU NEED A 2008 AUDI CHILTON REPAIR MANUAL.TO REPLACE TURBO YOU HAVE AT LEAST 60 COMPONENTS YOU HAVE TO REMOVE IN ORDER TO REPLACE TURBOCHARGER ME TELLING YOU IN WRITING WONT HELP YOU NEED TO LOOK AT PARTS DIAGRAM TO SEE PARTS YOU HAVE TO REMOVE AND DISCONNECT.

SOURCE: replace glow plug on audi a3 2005

If this is a Diesel engine, the glowplugs would be in a position like a sparkplug. You can replace them as you wish, or replace only the bad one. To determine if a glowplug is bad, you would remove it as you do a sparkplug on a gas engine.

With several of the glowplugs removed, you would place a battery jumper cable on one end of the glowplug, while being careful not to damage its threads. That cable would be connected to the NEG battery cable. The remaining cable would be placed on the Positive(+) terminal of the battery and then you would briefly tough the POS cable to the top of the glowplug.

Do this briefly. You can melt the part. But you need to see if the glowplug will glow. Often the problem with glowplugs is the Timer box. This is the box from where the wires come from to go to the glowplugs.

If you have a glowplug staying dark, or failing to glow well, then it is a bad glowplug. Each should glow the same. That is why you check several at a time to tell what is normal.

I work on Ford diesels and do not know what plastic covers you may have. So just follow the wires that are not on the fuel injectors and that is all you can possibly do.