I know this has been discussed thoroughly on other forums but I haven't seen an in-depth discussion on this forum so here goes. Car is a 2007 Z4M Coupe (E86M) its symptoms are - first radio audio cuts off, then ABS, DSC, and Brake lights flash on and off at times it feels like the brakes are being gently applied. If they stay off long enough the radio audio comes back on. Obvious candidates are Stability Control Module and/or speed sensors. Other forums suggest bad battery or faulty voltage regulator. My diagnosis started with measuring battery voltage with the car off. At battery terminals voltage was 11.5 volts - ah ha low. Started car to check alternator and voltage regulator, voltage at batter was 14.2 volts at idle and at 4,000 RPM, turned on A/C and lights, voltage at battery dropped to 14.18 volts at idle and 4,000 RPM - concluded alternator and voltage regulator are working properly. Connected battery to Battery Minder for 5 - 7 days, Battery minder indicator lights show battery is fully charged. Connected Bavarian Technic OBD II diagnostic cable and software (version 126.96.36.199) to car, to read Fault Codes, DSC module showed code 5E16 - can't clear fault. Test drove car with no indicator lights (test drive was about 12 miles with no restart of engine), battery minder was reconnected to battery. Next day test drove car 5 miles with no indicator lights, turned engine off and restarted engine, got indicator lights after 1 - 2 miles. Multimeter showed 12.5 volts at battery terminals. Talked to Bavarian Technics they suggested I check instrument cluster for fault codes, check show a couple of codes that all cleared. All were electrical in nature. Changed battery today finding light corrosion on the positive terminal, and test drove car. After 7 miles (about 10 minutes) with no engine restart symptoms appeared. Connected the Bavarian Technic cable to the car to check fault codes, the following codes appeared: 1. Engine - Fault code 2E7C Bitserial data interface, signal Error will not cause a warning light Error is not currently present Test condition have been completed Time out Was able to clear code 2. Dynamic Stability Control DSC Fault Code 5E16 DSC-ECU-internal: Failure Processing System Transfer Error. SP-interface timeout in System- Server Error will not cause a warning light Error is not currently present Test conditions have been completed Code will not clear 3. Steering Angle Fault Code 9 Not an ASC2 Message Was able to clear 4. Electronic Immobilise System 3 (EWS3) Fault Code 15 Power on reset Was able to clear All codes were read with the ignition key and emergency flashers on, battery minder connected, and engine off. Do these codes point to a speed sensor or Stability Control Module? Taking clues from the Hack Mechanic's recent article on this Z3 DSC my next step is to look for chassis ground issues but I've no idea if the Radio and DSC share a common ground point; in fact I have a hard time believing it. If the DSC fails does it cut power to the radio amplifier? If I am reduced to swapping parts with new parts until the problem goes away my next step is the Speed sensors, I saw on Pelican Parts web site the Delphi sensors were about 1/4 the price of BMW labeled sensors and ATE sensor were 1/2 BMW price. Does anyone have experience with Delphi or ATE. sensors? Lastly, I can't rule out a defective new battery; however, that is sort of immaterial as I plan to reinstall the old (4 years) battery tomorrow and return the new battery (AutoZone). Appreciate any help I can get and promise to post the final results when I get the problem fixed.