I bought a 330ci that had been in a minor accident (front end). I was told the fuel pump needed replacing and I did so. There is no power to the new pump and it cranks, no start. I checked fuse in ECU box and changed relay. The main code I get is 50B - MRS battery positive terminal isolation 1 and MRS power supply.
Hello there is a fuse on the positive battery post , its called the ibs, I can't remember if you can reset that one or if you have to get a new end
@BMW Workshop Thanks for the quick reply. Everything I researched on ibs indicates a no start - no crank. It is the same with the explosive disconnect on the hot wire ( no start-no crank ). When it warms up a little ( unseasonably cold in Oregon ) I will try to disconnect and bypass. This car cranks strong - it seems to be not getting any gas. There also seems to be a comm. problem with the ECU. The comm. box was crushed during the accident an needed to be replaced. There is 1 wire coming from a small harness that I am not sure where it goes. I will post a picture later today. Thanks again for your help. I think it is great that you started this forum :)
Here are a couple of pics. The unknown wire is the one with the circle connector. that comes out of the harness that goes into the ecu box