I have an ms Labs 96-97 ms3 mini and the problem is that after starting the car, the tuner studio cannot find the ecu. The car won't start either. I noticed that the 5v led doesn't light up at all, so the problem is probably there? Has something burned out in the ecu or where should I start looking for the fault. Or does anyone have a Schematic so I know to check if the fuse could be blown in the ecu.

 

I had a similar issue with my car's ECU a while back. It's definitely frustrating when you're all set to go, and then your car refuses to start. In my case, the problem was indeed related to a faulty power supply to the ECU. If your 5v LED isn't lighting up, that's a pretty clear sign there's an issue with the power. It could be something as simple as a blown fuse, or it might be more complex, like a problem within the ECU itself.

I'd recommend starting with the basics - check all the fuses related to the ECU. A blown fuse is often the culprit and is the easiest fix. If that doesn't solve it, you might need to get deeper into the ECU's wiring and components.

Also, for anything LED-related, I've found https://leds.to/ to be a handy resource. It's not directly related to ECUs, but it's great for understanding anything about LEDs, which might help in diagnosing your issue.