Audi 80 B4 TDI: Clicking sounds from magnetic valves after engine shut-off

Hello everyone!

I have already searched the entire internet for a solution to my problem, but I haven't found anything, so I am hopefully reaching out to you.

It's about an Audi 80 B4 1.9 TDI manufactured in October 1994 with a 1Z engine.

"For about a year now, I've been dealing with the issue of magnetic switches and valves in the engine occasionally clicking after I turn off the ignition and remove the key."

The electronic component on the fuel injection pump is particularly prone to making a clicking sound.
Sometimes, the two valves in the vacuum system also make a clicking sound.

The clicking sound stops only when you turn the ignition on and off again (without starting the engine).
The clicking sound doesn't always occur, and I haven't been able to identify any specific pattern. It might happen more often after washing the car or in wet weather, but I can't say for sure.

The problem is that if you don't think about it or don't hear the clicking sound due to ambient noise, the battery can be completely drained overnight.

Does anyone have any idea what this could be?
Thank you!

Hello.

Yes, I'm familiar with that problem. In my case, it was caused by the ignition switch, which occasionally failed to completely disconnect all circuits when switched off.

Replace the circuit board on the back of the ignition switch and it's good as new .

Part Number: 4A0905849B

From the accessories: €15.
Audi: €44.

Another possibility would be a "stuck" relay for the engine control unit, which would then always be on and consume power.
It is located in the auxiliary relay holder on the driver's side, under the dashboard, it has a metal casing, and usually has the relay number 300 printed on the top.

Part number: 89 7184 000.

Regards,
Mpire

Hello Mpire,

Thank you very much for the tip.
I'll replace the part next week and let you know about the results afterwards.

Hello Mpire,

Okay, I replaced the ignition switch a few days ago.
Since then, the clicking sound hasn't reappeared, so it was probably caused by that issue.
Thank you for the tip!

Sure, here is the translation of the text from German to English:

"Best regards," or "Sincerely,"

Hello.

Great, thanks for the feedback .

Regards,
Mpire