general problems of the 2003 BMW M3

Tl the contact owns a 2003 BMW M3. The contact stated that the electrical system shorted out and all the electrical devices failed to work. The vehicle decelerated without warning and the engine went into limp mode and lost power. All the warning indicators illuminated on the instrument panel. The vehicle was towed to an independent mechanic who diagnosed that a new battery was needed and a part on the fuse box needed to be replaced. The manufacturer and dealer were not made aware of the failure. The failure mileage was 98,000. The VIN was unknown.

P133 code has come up after driving 100 miles. I took the car to a local mechanic in which he replaced all oxygen sensors. A few weeks later the code came back up. I took the car back to the mechanic in which he said it has to do with a faulty ecm. This has caused me to fail smog test unless I erase the code. The ecm has already been reflashed by BMW back in 2012.