1Z Problems: Another One! (SEO Optimized)

Translated on 11-10-2026, 17:19.

Hi fellow DIY enthusiasts!

This time, it happened to a friend's A4 TDI 1Z, manufactured in 1995, with 220,000 km on the odometer.

Shortly after starting (1-3 seconds), the engine shuts off. It doesn't matter if the engine is cold or warm. The problem doesn't always occur, and there are no issues while driving (-> full power). Sometimes it takes 4 attempts to get the engine started. Once the engine runs for longer than 5 seconds, it doesn't shut off again.

Was könnte das sein?? Wegfahrsperre? NBF is new!!

I have this nagging feeling that soon, the three of us – my friends, my father, and I – will be frequenting this place

.

Thank you in advance

.

Best regards, Christian.

Guest Free account, no CAN development support

Hello,
That definitely sounds like an immobilizer problem. I would try disconnecting and reconnecting the connector at the reading coil on the ignition switch a few times; that should fix it. However, you'll need to remove the airbag, steering wheel, etc. to do that!

Translated on 11-10-2026, 17:20.

Hello,

Before dismantling anything, I would first read the error codes. This might give us a more precise indication of the problem.

Translated on 11-10-2026, 17:21.

Hi everyone!

Thank you for the quick responses!!! Ulf's adapter is not finished yet, and then... That sounds like a common problem

.

Best regards, Christian.

Translated on 11-10-2026, 17:22.

haehnlein wrote:

Shortly after starting (1-3 seconds), the engine shuts off. It doesn't matter if the engine is cold or warm. The problem doesn't always occur, and there are no issues while driving (-> full power). Sometimes, it takes 4 attempts to get the engine started. If the engine runs for longer than 5 seconds, it won't shut off again.

Hi Christian,

If the engine always starts without hesitation (no signs of trouble) and then immediately stalls from a smooth, stable idle, as if the key was just turned, it is most likely due to the immobilizer system.

However, if it sounds "strange" before it stops (e.g., a rough idle, unusually hard or soft running, etc.), the problem is likely elsewhere (e.g., fuel supply issues, a stuck valve, or resistance in its line...).