Engine won't start when the radio is on

Hello everyone,

'I recently became a TDI driver and am new to this forum. I drive a Golf IV TDI (90HP + chip) manufactured in August 1998, and I'm experiencing the following problem. Whenever the radio is turned on, the car won't start. The starter motor runs, the engine turns over a few times, and then dies. If I then turn off the radio, I have to try starting it 1-2 times before it works. If the radio is on from the beginning, the car starts immediately without any problems. I've already connected an additional battery, but I'm experiencing the same problems. Therefore, I assume that the battery is okay. Also, there are no problems when I start the car with the headlights on.' The problem can't be the radio itself, because it occurs with both the original radio and the current Blaupunkt unit. What else could it be? I definitely don't want to be constantly turning the radio on and off.

Thank you very much.
Thank you for your help.

Daniel.

Hmmm, let me guess:

'You don't have the original radio installed, and you haven't disconnected the diagnostic bus cable?'

Hmm, that's a good question.
I had it installed there right away, where I bought it (A.T.U.), because I knew that VW had swapped something out. I didn't want to try to figure it out myself. The mechanic then reconnected 2 cables and connected the radio according to the pin configuration in the manual. However, I think the VW GAMMA system had the same problem. Which cable might need to be disconnected or not connected in order for it to work again?

Regards,
Daniel.

Hmmm, do you think or know if the same thing happened with the gamma version?
Because if that was the case, then it shouldn't be due to that.

Have you had the error codes read to see if anything is already stored there?

I once had the error memory read out, and it indicated a problem with the engine control unit. They cleared the error, but it didn't reappear, even though I'm still having starting problems. If I know which cable to disconnect, I'll just try it. It can't possibly get any worse than it is now, right?

Hmmm, no, it can't get any worse.
I'm just not sure which pin the cable for the self-diagnosis function is connected to right now.

'Did the error log mention anything about the 'Engine Control Unit locked'?'
Okay, I'd try a different key, because this message usually comes from the WFS, and that's often due to the keys. But if the key isn't re-entered, then it probably isn't the cause.

Thanks for the tip, I just found it. Pin 3 (white/gray) needs to be disconnected.
I'll try it out tomorrow and get back to you.

It could also have been 'engine control unit locked.' That seems more likely now. But I only have one main key with lights and one secondary key. I'll also try the other key without lights tomorrow. Can the keys only be registered using the diagnostic tool, or can it also be done by the user themselves?

It can only be done through the diagnostic tester and the workshop.
*Unless someone has already figured out the logic behind the VW/Audi PIN code?*

So, it wasn't the key, but it was the cable for the self-diagnosis function. I turned it off, and now everything is working.

Thanks again for your help.
Daniel.

See...? It works... now even without a cable...

Hello!

@ Vagtuning:

What do you mean by the logic behind the VW PIN? The new 7-digit [something].

Best regards,
Frank.

Sure, that's exactly what I'm looking for... Is there a program for calculating that?
So... Is the combination of the vehicle registration number + immobilizer ID a valid 7-digit PIN?

No, probably not... and if it does happen, hardly anyone here will reveal it... if it does, I'd be happy to receive mail ).

Hello!

What do you need the 7-digit PIN for? Or is it about a PIN in general?
Since VW is now providing the 7-digit PIN for older vehicles as well (which previously only had 4-digit PINs), the process must work in reverse.

The VAS 5051 calculates a 4-digit code based on the current date, dealer number, importer/authorized service provider number, and a 7-digit PIN, and transmits this code to the control unit.
The 7-digit code for the VAS 5051 is only valid for the day it was requested (unless the date on the 5051 is changed) and can only be used with the 5051 device belonging to the requesting workshop. With VAG-COM, you can use both 4-digit and 7-digit PINs; you only need the operating numbers and the date of the request.
I don't believe the vehicle identification number (VIN) is used in the calculation of the 7-digit PIN, because in previous inquiries (when PINs were 4 digits long), the VIN was not transmitted.
I don't know if there used to be an algorithm that allowed someone to determine the PIN from the transaction number (all requests were online, but a calculation could also have been done locally), but it would certainly have been possible.
It is possible that the request actually searched a database containing the Stg.Nrn (company numbers).

Anyone who knows the algorithm is welcome to contact me .

Best regards,
Frank.