I need your advice with the problem I'm facing with my M3 E36 Euro.

The car has a loss of power specially in low revs, with a hesitation when trying to accelerate, and allot of exhaust fumes.
I took it to a BMW workshop, and when the technician connected the diagnostic system (Modic) there was no communication with the ECU, so he could diagnose.
Do you have any idea of what it may be wrong?

Thank you in advance,

Best Regards,