Touran 1T - does not start, No 15 terminal

Hello everyone,

My Touran 1T1 (1.9 TDI BLS, year 2009, ~191,700 km) no longer starts.

Maybe someone knows about this problem.

Symptoms:
• Yesterday evening, it was still running, but this morning it wouldn't start (the battery was probably completely drained (5.4 V)). After ADAC assistance, I drove home for about 40 minutes, and the battery was fully charged again.
• To check for the cause of the leakage current, I removed all fuses and measured between the battery's negative terminal and the ground cable (no anomalies detected). After that, almost nothing happened anymore…
• Control lights on the instrument panel remain off even with the ignition on. Other consumers, such as Radio, lights, window controls, and the wireless security system are all functioning.
• Various control units are no longer accessible via VCDS.
• Relay 643 (J682, Terminal 15?) and Relay 460 (Terminal 75) both click when the start attempt is made.
• I don't know if it has something to do with this, but: In February, the steering wheel warning light blinked at the same rhythm for a few days and then disappeared…
• Previously reviewed:
• All fuses are OK (visually & continuity)
• Safety clip (1K0 937 629A) tested with fuse clips ▔ 12 V at all outputs.
• Replaced starter motor (1K0953503) → no change.
• Charge both batteries again and install them alternately. Also, additional starting assistance provided: No change.

I have attached a log from 26.08.2025 and one from today. I even obtained the circuit diagrams (over 2700 pages ).

If anyone could offer me some assistance here, that would be fantastic! However, with so many errors, I don't even know where to start

Hi!
Please turn the vehicle off completely for another 10 minutes. Main fuses (strip fuses) also checked?

Basically, I would start by investigating why the 09 model is reporting an error for a missing terminal 15 in the interior...

Best regards
brezelmann01

Hi,
and then in all STGs, delete the error entries relating to "low voltage".
What I notice:
- "Diagnosis interface incorrectly coded" error - how did this happen? The error can block a lot of interaction, and should be fixed urgently.
- km- Stand: at the beginning of the car scan is 191760. However, some STG´s (Central Electrical, Comfort System) show 191767. The distance traveled counter is located in the instrument panel, and the status is transmitted to the other STG's.
- Communication is lacking not only with the VCDS, but also between STGs. The status changes during the scan. Is there an improperly installed interface behind it?
hg
Herbert

After 49km, a deeply discharged battery is not fully recharged.

24 hours with a good charger and power are needed or replace it immediately.

brezelmann01 wrote:

Hi! Please turn the vehicle off completely for another 10 minutes. Main fuses (strip fuses) also checked? Basically, I would start by investigating why the 09 model is reporting an error for a missing terminal 15 in the interior... Best regards brezelmann01

- I have re-thoroughly disconnected the vehicle.
- I re-checked the main/fuse box in the engine compartment, using a multimeter and even a 100-watt light bulb.
- I'm not quite sure yet where/how to start my search for the missing clamp 15. I'm currently overwhelmed by the electrical diagrams.

Below is a current error scan from today.

Herbert wrote:

Hi, and then in all STGs, delete the error entries relating to "low voltage". What I notice: - "Diagnosis interface incorrectly coded" error - how did this happen? The error can block a lot of interaction, and should be fixed urgently. - km- Stand: at the beginning of the car scan is 191760. However, some STG´s (Central Electrical, Comfort System) show 191767. The distance traveled counter is located in the instrument panel, and the status is transmitted to the other STG's. - Communication is lacking not only with the VCDS, but also between STGs. The status changes during the scan. Is there an improperly installed interface behind it? hg Herbert

- Can the diagnostic interface code itself automatically - I haven't done anything? Or, how can I properly encode it?
- These could be residual KM stands, where the control units were accessible before the connection(s) was/were interrupted.
- Meint "Interface" das Diagnoseinterface (Steuergerät 19) oder mein VCDS-Stecker? Ich habe immer die VCDS-Updates installiert, wenn das System mich dazu aufgefordert hat. I wouldn't know whether or not I could make mistakes there.

Rüdi wrote:

After 49km, a deeply discharged battery will not be fully charged. 24 hours with a reliable charger and power are needed or you'll need a new one

- I of course did that + I also gave it the full starter kit. Let's double-check for safety today.

I have apparently found the error. I must have removed and tested the fuses in the engine compartment and, in the process, not put the fuse (F7) back in its correct location. However, I did check this, but: According to the original wiring diagrams, this fuse was actually only "active" from May 2009 onwards. However, my Touran has a production date of April 2009, which is why I didn't notice it.