2006 Passat 2.0 tdi help!

I've had my 2006 Passat 2.0 tdi for about 7 months of trouble free motoring, but tonight that all changed.

I was driving home from work in a typical non-aggressive manner, and stopped at some traffic lights. As I pulled away the mpg on the dash display suddenly dropped, the power then dropped, the car slowed to a standstill and wouldn't restart. The display said “check engine” and “garage” or something similar.

I was towed to a fuel station as the mechanic thought I might have run out (I had about an eighth of a tank left) and put 20 litres in. The car started with no issues, so I moved it and turned the engine off so the mechanic could have another look. After this it started but then cut out. It then would turn over but wouldn't start, and if it did manage to start it wouldn't hold the revs before cutting out again. The mechanic checked the fuelling was OK (which it appeared to be) and also checked for fault codes of which there were none.

After this, I was towed home and told to leave it a few hours before trying again. When I tried again, it wouldn't start and after a few attempts the oil light flickered on and the dash displayed “STOP” which has now got me slightly concerned..

The car has only done 90k miles and is due a service soon but not just yet. Does anyone know what could be the problem before I take it to a garage?

Any help would be greatly appreciated!

Apologies if this is in the wrong section, I couldn't find the area for Passat B6's!

Not so many Passat B6's here, as they were never sold in North America.

I would scan for codes, and if none, I would start by verifying fuelling.

Have you changed the fuel filter any time recently?

If yes, I would verify that the in-tank pump works - turn the key to on, and listen to see if the in-tank pump runs for a couple seconds. If not, I would check to see if it is getting power. If not, you'll need to locate it's relay and check for function.

If the in tank pump checks out, then I would look to see if the engine is supplied with the correct amount of fuel - if yours is a PD engine, I would be looking at the tandem/fuel pump as a possible suspect.

All that said, the car should be put in the hands of a diesel mechanic with experience, in order to get a proper diagnosis.

Thanks for your help- I've had a technician out to look at it today. He's spent 3 hours looking for the problem but can't find the issue, the fuelling is absolutely fine.

The only fault being shown is a faulty relay, but he couldn't find one that doesn't work. Apparently there is an upper and lower relay in the engine, but he couldn't find the lower one- any ideas?