I just aquired a 95 740I that has been sitting outside for around 3 years. It probably has some water damage. It actually started up after charging the battery. It is running rough at idle. As the engine revs higher it smooths out. The check engine light is on. I retrieved the code 1A (control unit supply). Is this just the power going to the control unit? Definetly need some help first time working on a BMW:help

Check the charge rate at the battery with a multimeter.should be over 13.7/13.8 volts ideally.

Thanks I will check the voltage at the battery tommorow