Hey all! Long time listener, first time caller. My 2002 A6 quatro was running just fine and then would not start the other day. Starter turns the motor over, but it doesn't even try to run. I found no fuel pressure at the intake manifold and the pump was not running. I bypassed the relay and the pump runs, so I replaced the relay. Still nothing. I checked all fuses and all the connections under the hood. No CEL codes either. My wife drove it home from work and parked it and then nothing. Any ideas? Battery is fully charged (and newish)

 

have a similar issue with my 2002 Audi A4 quattro 3.0 just died at a stop sign. I checked the fuse for the fuel pump, no power to the fuse, I replaced the relay, still no power to the fuse.
I read on a similar thread that the camshaft position sensor if bad would cause this..
I think I need to check the fuel rail for fuel pressure or possibly replace that camshaft position sensor.

 

So after doing some more searching around and talking to a couple mechanic buddies it turns out the fuel pump relay is a common problem on these, but other problems will also cause the fuel pump not to work. Both my buddies, one of whom works at an Audi shop, said the relays go out or get stuck, but that usually will trigger a bunch of CELs so they thought it was strange I didn't have any. $40 relay did not solve my problem, and it turned out to be the temp. sensor of all things! It had broken internally and leaked coolant into the plug area which must have made the computer shut the fuel system down. I have also heard that the camshaft position sensor is a common culprit. 135,000 miles and this car is on temp sensor number 4 now. WTF?

 

 

I actually had a CEL a while back for the temp sensor and already had the part, so I just replaced it and the car started. It is a pain in the butt to do and the gauge was working fine, so I hadn't done it yet. Like I said, this is the 4th one on this car, but it's never made the car not start, so I wasn't in a big hurry and didn't expect that to be the problem. The other sensors that have failed have never had coolant inside them though, so it must have shorted out the connector (in fact the pins were rusty so this must have been going on for a while). I could tell right away that changing the sensor was the right fix because the car sounded normal while starting, whereas before it was just spinning and not even sounding like it usually does when turning over on startup.