G Klasse Diesel Starting Issue Resolved

Wow, that sounds frustrating! I had a similar issue with my G Klasse (though it's not the same year). "Terminal 15 ignition positive interrupted"... yeah, that rings a bell. For me, it was definitely a connection problem. Did you check all the ground connections as well? A bad ground can cause some seriously weird electrical issues. Also, have you noticed any other electrical components acting strangely, like interior lights flickering or anything like that?

Thanks for chiming in! When you say ground connections, are we talking about the ones directly connected to the chassis? And no, I haven't noticed any other weird electrical symptoms. Everything else seems to be working perfectly fine, which is what's making this so baffling. What exactly was the connection problem on your G Klasse? Was it a specific plug or section of the wiring harness that was the culprit?

Yep, I mean the ground connections bolted to the chassis. Clean those up, make sure they're tight. Honestly, mine was a pain to diagnose. I ended up taking it to my trusted mechanic. He found a corroded connector in the wiring harness near the starter. Since you're already getting that error code, and the shop suspects a cable or plug, it's probably best to let them trace it down. Especially if you haven't seen any other electrical oddities.

Thanks a bunch for your help! I took it in, and you were spot on – corroded connector in the wiring harness, just like yours! They replaced the defective connector, and everything is back to normal. The final bill was 95€, which I was very happy with. Appreciate the advice!