E46 problem, help!

[Cloggy Saint]

something very weird has happened to my old man's E46 318i auto. I just gave it a clean and re-set the clock and now it won't start. When i turn the key there's a rythmic knocking from the engine bay, all the dash lights flash, the needles flicker and the lights come on, no cranking at all. What the hell's going on, i know nothing about these cars. Help, i don't want to give him another reason to hate me!

[maxfield]

Sounds like the battery is flat to me.

[darkchild]

Sounds like the battery is flat to me.

Yep, had exactly the same symptoms on my old E46 318ci.

[Cloggy Saint]

Thanks, it was the battery. Very strange symptoms for a flat battery, it sounded much more serious than that.

[Speedtouch]

A lot of modern cars exhibit this behaviour when the battery is below the threshold voltage required by the electronics.