Yellow preheating light stays on

Hello,
I came across this forum because I've been having problems starting my 1994 Passat TDI, with a 1Z engine, for the past few weeks, especially when the weather is hot.
My question to the readers here: Has this error been observed more frequently before?
If the Passat is parked in the hot sun, it won't start even with a cooled 109 relay. During the starting process, the yellow preheating lamp doesn't turn off, but it also doesn't blink.
The only solution is to short-circuit the 109 relay. After it cools down or after a short drive, I can then replace the malfunctioning relay, which will then work again.
This error was only posted for engine control units manufactured between April 14, 2000, and July 12, 2000, and once as a 'soldering' error related to the immobilizer of the 1994 TDI model (in this case, the engine cut out while driving, which it hadn't done before).
Are there any other experiences in this area?

With greasy greetings.
Pöl_Passat
(My Passat runs on vegetable oil.)

1. Respect to whoever drives a TDI with Poel. I don't dare to do it myself; instead, I treat my colleague's JX with Poel (Mensa french fry oil ).
I've heard too much about blown pistons in TDIs.

Have you only put the 109 in the refrigerator, or have you also bought a new one?

If you suspect that part is the problem, I wouldn't hesitate to replace it, or is it too expensive?

m;

Hello,
I actually don't see any problem with driving the TDI at 200 km/h on the highway using plant oil (not biodiesel) or achieving fuel ranges of up to 1900 km with it. Take a look here (http://www.strutzberg.de/demo/Auto/Tagebuch.htm).).

I even resoldered the 109 components (around 11 euros each), and one relay is stored at room temperature. It seems like either all 3 relays fail, or none of them do. Unfortunately, I can't just drive to the workshop, because the last time, this error didn't occur there.
During the starting process, the yellow preheating light simply doesn't turn off, and nothing else happens. I then remove the relay and bypass it using a trick from the ADAC (German automobile club). Then I can start the engine.
After a few attempts, I installed one of the many 109 relays, and the yellow light then went out as it should.
I just don't want to have all sorts of parts replaced unnecessarily, maybe there's just a cold solder joint in the control unit.


Sincerely,
Pöl_Passat

Have you ever had the error memory read out?

"Gluehwendel" in the context of a TDI engine refers to a motor control unit (ECU) check light.

If they remain connected, the control unit (STG) must be doing so "intentionally." Normally, it should also be able to provide a reason, i.e., store an error code.

m;

Hello,

According to the last workshop visit, the issue wasn't actually a real problem.
After the relay was reinstalled, the error didn't appear anymore. However, the error only occurs sporadically. I just hope that the error manifests itself consistently so that I can take the car to a workshop. Only then will a proper troubleshooting process be possible. Right now, the TDI starts normally, but I'm not entirely confident in the engine's stability.


Sincerely,
Pö-_Passat