2003 M3 SMG lots of warning lights on intermittently

[IanColvin1000]

Hi

Hope someone can help. Got a 2003 M3 SMG week or so ago. A couple of times now, the following has happened. During a gear change, for about a second, 4-5 warning lights come on (inc. central DSC one) and the radio cuts out then they all go out and its all fine. Got it booked in for a diagnostic check with BMW but wondered if anyone has a clue what it could be. Only happens intermittently.

Cheers
Ian

[M3CS]

IanColvin1000 said:

Hi

Hope someone can help. Got a 2003 M3 SMG week or so ago. A couple of times now, the following has happened. During a gear change, for about a second, 4-5 warning lights come on (inc. central DSC one) and the radio cuts out then they all go out and its all fine. Got it booked in for a diagnostic check with BMW but wondered if anyone has a clue what it could be. Only happens intermittently.

Cheers
Ian

99% of issues with electrics on these cars turn out to be due to weak batteries. Is the car getting a lot of use and does it have a BMW/ Bosch battery? If 'no' to either, my money is on battery.

Could also be a loose connection to the battery. Check for corrosion on the terminals.

If you hadn't mentioned the radio issue, i'd have suggested any one of the brake/speed/angle sensors used by the DSC system could be faulty; but the presence of the radio issue made me think "battery.". I had a load of issues with warnings for dsc/abs and even smg failing to change gear. Fixed by replacing a faulty brake pressure sensor.

I guess the other possibility is alternator?

[IanColvin1000]

Thank you and for such a fast response. Will check battery but that's reassuring what you say. Cheers