Q: My BMW can't go over 5 mph

Your car has an electronic throttle motor, which opens the throttle when you step on the accelerator. It’s possible that the throttle is not activating with the pedal. A problem like that should be accompanied by a check engine or other warning light. You didn’t mention if there were any warning lights on your dashboard, so if there are not, try turning on the key without starting the car, all the warning lights should be on. This is a bulb check feature, I’m betting your check engine light is not working. Either way, there should be codes stored in your engines ECU that can help point you in the right direction for a fix, but reading them requires specialized equipment. By contacting your mechanic, you can have a technician come to your home or office and check out your car and advise you on what needs to be done about it.