Alpina E46, problem after flat battery?

[Legacywr]

So, not used my Alpina B3S cab for quite a few months, so obviously had a flat battery.

I charged it in situ (should I not have done this?) but, now, the dashboard is flashing in various ways, and the 'check engine' light is on!

Any ideas?

[naturalaspiration]

If you disconnect the battery and leave disconnected for a little while (turn on say parking lights just to use up any remaining charge) and reconnect again?

Can you start the car or not?

[Legacywr]

I've taken the battery off this morning, and put on charge, we'll see later

[Sardonicus]

Legacywr said:

I've taken the battery off this morning, and put on charge, we'll see later

It has gone flat/totally discharged and its been left for even a few weeks like this the battery is probably toast now anyway do the right thing fit new and the correct rated branded unit Varta Exide Bosch etc

[ds666]

This happened to me last year after it was off the road for the winter and resulted in major issues that took 3 garages to sort . Each time I started it there were different warning lights - no brake lights , etc etc . I had had it on trickle charge but used it and forgot to reconnect . Battery ran flat , jump started it . Canban issues .
I only ever charge the battery now with the negative lead disconnected .

I wish you more luck than I had

[Legacywr]

Gulp!

[ds666]

The actual fix was pretty straight forward in my case but v difficult to diagnose . You may be lucky once the battery is ok but best to charge as noted in future .

[KPB1973]

Failing batteries on my last 2 E9x BMWs caused all sorts of random problems and error codes (o2 sensors, NoX sensors, temperature sensors etc triggering warning lights) but a new battery - registered to the car - solved them all.

[Sardonicus]

All computers , modules etc all have a voltage operating threshold if you drop below this they throw out spurious junk/ fake fault codes hardly surprising really

[Mr Tidy]

Sardonicus said:

All computers , modules etc all have a voltage operating threshold if you drop below this they throw out spurious junk/ fake fault codes hardly surprising really

True, but BMWs seem to manage to throw up random faults even when the battery is still able to start the car - my E86 lit up an amber EML.

Drove it to my BMW Indy for a diagnosis, and he called to say it needed a battery so I told him to change it. Fault was CAT System Efficiency on both banks - fault cleared and no repeat (so far in 2 years).

[Sardonicus]

Mr Tidy said:

True, but BMWs seem to manage to throw up random faults even when the battery is still able to start the car - my E86 lit up an amber EML.

Drove it to my BMW Indy for a diagnosis, and he called to say it needed a battery so I told him to change it. Fault was CAT System Efficiency on both banks - fault cleared and no repeat (so far in 2 years).

This is true i'll grant you

[Legacywr]

Well, I’ve given the battery a full charge, it’s the right battery for the car, and, the indicator fitted to it, says it’s in good condition. Should I still fit a new one?

[ds666]

Did you fix it ?

[Legacywr]

Not yet, I forgot I had a battery conditioner, so, I’ve put it on charge again, give it another try, if it fails, I’ll invest in a new battery.

[Legacywr]

Good old CTEK!

Battery recoverd, car started, thanks for your help guys

Just out of interest, is this sort of situation that threw up all the fault codes, that were read off when my car was last serviced?

[Sardonicus]

Your car probably threw out all that garbage/hash/fault codes because the battery went flat or failed attempts to jump start