VW Golf TDI Starting Issue Points to Terminal 30 Fault

As someone with moderate experience working on VWs, I had a very similar issue with my 2014 VW Jetta TDI last winter. The symptoms matched exactly what you describe, weak cranking and multiple start attempts needed. After checking the obvious elements like battery terminals and starter motor connections, my mechanic found that the main wiring harness had deteriorated where it connects to the fuse box. This caused intermittent power supply issues affecting the whole starting circuit. The repair involved: Complete circuit testing of the ignition switch system, Replacing damaged sections of the wiring harness, Installing new fuse box connections, Recalibrating the starter motor circuit breaker Total cost was 290€ for parts and labor. Since the repair, starting has been consistently strong and immediate. To help diagnose your specific case better: Have you noticed any other electrical issues? Does the problem get worse in wet weather? What voltage reading do you get at the battery during cranking? Has the check engine light appeared? The terminal 30 issue you mentioned could definitely be related, but knowing these details would help narrow down the exact cause in your Golf.

After having the repairs done, I can confirm it was indeed the ignition switch causing the intermittent starting issues. The voltage drop test revealed poor conductivity through the switch assembly. My mechanic found corrosion inside the switch housing that was interrupting the circuit. Complete repair involved: New ignition switch assembly, Terminal cleaning and protection, Charging system diagnostic, Updated software for the starter control module Total repair cost was 180€. Car now starts perfectly every time. This matches others experiences in the forum with similar symptoms on the MK6 platform. Last service completed at 105000km, currently at 105756km.

Thanks for the update on your Golf's ignition switch repair. My Jetta had the exact same symptoms, and while the initial diagnosis pointed to the wiring harness, we eventually discovered multiple issues affecting the power supply circuit. The charging system diagnostic on mine revealed that the problems extended beyond just the ignition switch, there was also corrosion building up in the main fuse box connections. After cleaning those connections and replacing the ignition switch assembly, the starting issues were completely resolved. One additional tip based on my experience: have your mechanic check the circuit breaker ratings during your next service. My electrical fault turned out to be partly due to an incorrectly rated breaker that was causing intermittent power supply interruptions to the starter circuit. My repair stats were similar: Initial repair at 98000km, Current mileage 112000km, No starting issues since fixing both the ignition switch and fuse box Good to hear your car is starting reliably now. These electrical gremlins can be frustrating to diagnose, but at least the fix was relatively straightforward and cost-effective.

After comparing repair experiences, I feel more confident about the work done on my Golf. The ignition switch replacement definitely solved my starting problems, and the additional checks they performed on the charging system were worth the investment. The voltage drop issues were exactly as described by others, the starter motor would struggle due to poor conductivity through the corroded switch. Having the terminal connections cleaned and protected should prevent future electrical faults. My repair costs came in lower at 180€ versus the 290€ for the more extensive wiring harness work others needed. The power supply is now stable and consistent. No more multiple attempts needed to start the car. For reference, here are my final stats: Repair completed at 105000km, Now at 105756km, Zero starting issues since fix, All electrical systems working perfectly Will definitely keep monitoring for any voltage drops or starter motor hesitation, but so far the repair has completely resolved the problem. Thanks for all the helpful diagnostic insights from the forum.