Mercedes B Klasse Hybrid Transmission Issue

That sounds familiar! I've got a B Klasse too, though not the hybrid. I had similar issues with the transmission. The engine wouldn't start sometimes, and the shifting was jerky. Did you check the transmission fluid level? Is the check engine light constantly on, or does it flicker? It could be a simple transmission sensor issue, but these modern transmissions are complicated. Did you notice any pattern before the transmission got worse?

I did not check the transmission fluid level; is that something simple to do? The check engine light is constantly on. You say it could be a transmission sensor issue? Could that really cause the engine not to start? I thought that was only related to the shift lock. What was your experience? Was the repair costly?

Checking the fluid level can be straightforward, but you'll need to know where to look and what kind of fluid to use. Given the other symptoms, and especially since the engine won't start, it's probably more than just low fluid. I had similar symptoms, and it turned out to be a faulty control unit, just like you suspected. I'd recommend taking it to a workshop. They can properly diagnose the issue and give you a more accurate estimate. Don't risk making it worse!

Thanks so much for sharing! It helps to know someone else had a similar problem. I took it to the workshop, and you were right, it was the control unit. It cost me about 1000€, but at least it's fixed now. I appreciate your help!