Passat TDI: Starting Problems - Troubleshooting Guide

I'm having a strange issue with my Passat 1.9 TDI, manufactured in 2003, with 120,000 km on the odometer.

'Occasionally, the car doesn't start when it's warm. I turn the key, all the indicator lights come on, the starter motor turns, but there's no ignition. This can happen several times, always with the same problem. Then, suddenly, the car starts without any issues. After that, I can start it repeatedly without any problems when it's warm, until this error occurs again without warning. There are no problems while driving, and of course, not during a cold start either. Otherwise, the car has no other 'issues'.'

For me, the potential culprits are the immobilizer, the diesel pump, and the relay for the diesel pump (if there even is one). I recently replaced the battery, as it's often a cause of mysterious problems. However, unfortunately, the problem has reappeared just 14 days after the battery replacement.

'Because the error occurs very rarely and sporadically, I can't provide a more detailed description. I only have the impression that after turning the key and before starting, there's usually a brief clicking sound in the dashboard and a suction noise (from the relay - which one? - and the diesel pump in the trunk), and I don't hear these noises when I'm experiencing the starting problems. By the way, the error memory is empty.'
Does anyone have any ideas?

Please specify the MKB (engine code). "1.9 TDI" is a very broad term.

Did you read the error codes? Also, the engine code is missing! Everything else is just guesswork.

ToniToni wrote:

As potential causes, for me, the immobilizer, the diesel pump, and the relay for the diesel pump (does that even exist?) are possibilities.

If the WFS (Wireless Front Sensor) is the problem, the WFS indicator light on the instrument cluster will flash. In that case, the car would briefly start and then shut off again due to an incorrect code.

The diesel pump relay itself is less likely to be the problem, but it's worth checking the relay labeled "109" (use the search function here to find "relay 109"). If that relay is faulty or causing intermittent errors, nothing will work.

And as Michael already mentioned, everything else can only be diagnosed more precisely once your engine code is known.

Okay, so, according to the service booklet,
3B6 262
96kW TDI SG6
and further digits in groups of three.

I hope you can make use of this; otherwise, please don't hesitate to ask.

Thank you and best regards!

ToniToni wrote:

So, in the service booklet, it says 3B6 262 96kW TDI SG6 and further digits in groups of three. I hope you can make use of this; otherwise, please don't hesitate to ask. Thank you and best regards!

Well, it's not the ideal engine, but since it's a 3BG with 130 horsepower and a 6-speed transmission, it can only be an AVF. The engine code is on the sticker in the service booklet.

Hi, I'm looking for an AVF relay, model 109. Here are some search results:
/viewtopic.php?t=21174&start=0&postdays=0&postorder=asc&highlight=avf%20relay%20109

Relay 219 in the fuse box?

Hey Toni, if it was the relay, please report it properly.
so that I can be happy.
and others get an important clue when searching, unlike you, who initially found nothing!

Access to the relay box, Passat 3BG: And what if you ever need to remove the blind plug?

It could also be due to an insufficient initial speed; what is the current speed?

Best regards, Rainer.

Low starter motor speed and defective batteries can also frequently cause warm start problems in the BKD engine (which, in this case, refers to the 2.0-liter 16V version).

ToniToni wrote:

I've done some research online: Removing the wiper arms and brackets is no problem, but the glued-on windshield deflector is supposed to be removable, ideally by breaking off the deflector itself, but in the worst case, by breaking the windshield. I can't believe that VW installs fuses and relays in a box and then covers it up with other parts in a way that seems "professional" but is actually hiding something. Does anyone have a clue?

The windshield wipers and deflectors can remain in place. Nothing needs to be broken or damaged. The blind plug is located in the deflector, directly above screw number 5, which is underneath the driver's side wiper arm. Its purpose is to allow access to this screw. I took the photos to eliminate any ambiguity.
Drive the wiper to its uppermost position, turn off the ignition. Reach under the wind deflector and push the plug upwards. This clears the way for a quarter-inch tool. Directly below the hole that is now visible is screw number 5.

Unfortunately, the original poster did not implement any of the suggestions provided. I hope this topic helps readers who are able to implement these suggestions and who are grateful for such assistance, while also allowing them to filter out the irrelevant content.