C30 Electrics : - Buzzing sound after replacing battery

anacortesian · Jun 5th, 2020, 17:48

I bought a 2009 C30 (2.5L Geartronic) 6 months ago from a private party with low mileage. The car just had it's 60,000 inspection at the dealer a month earlier and the only issue advised was low cranking amps on an older battery. The car started and ran fine so I put off replacing the battery for a later date. Then about two weeks ago the battery finally dies. Understandable. Luckily it died while the car is parked in my garage. So there was no towing or jump starting...I simply went out and bought a decent new battery and replaced it myself in the garage. Remembering to remove the negative terminal first as well.

The weird thing is with the positive cable connected first and the negative cable then being attached (which I believe is the correct procedure)...there was this rather loud and distinct "buzzing" sound seemingly at about the middle of the engine bay...as if some relay berried there were going crazy for a few seconds...then it stopped. The car started and ran fine (though the next day there was a urgent warning seat bag light on the dash which I am dealing with and assuming to be an unrelated issue from what I have been learning about that code CFFF...and which could be caused by any number of other issues)
Anyone has had this "buzzing relay sound" issue after replacing a battery?

KevMan2015 · Jun 5th, 2020, 20:54

Hello again, is this buzzing constant? Does it only happen when ignition is put on? After engine has stopped? Engine running?

anacortesian · Jun 5th, 2020, 22:03

Quote:

Originally Posted by KevMan2015

Hello again, is this buzzing constant? Does it only happen when ignition is put on? After engine has stopped? Engine running?

No...this was a one time occurrence...happened as I actually changed the battery...as soon as I made contact with the cables...BZZZZZZZZZZZZZZZZZ. Then it stops...and not heard from again...but you know...you say "what the hell was that?"

And...you know...I can't really justify any significance to the air bag module failure code I've got now... As that was the next day.... and I'm thinking a separate issue.

ukojesita · Jun 6th, 2020, 07:20

My V50 makes a buzzing sound, for about 3 seconds, every time I reconnect the battery. I think that it is a normal behaviour.

KevMan2015 · Jun 6th, 2020, 10:56

It could possibly be the EGR valve actuating the flap really quickly to clean any carbon/soot etc.
If it’s not happening all the time I wouldn’t be too worried about it.

anacortesian · Jun 6th, 2020, 19:00

Quote:

Originally Posted by ukojesita

My V50 makes a buzzing sound, for about 3 seconds, every time I reconnect the battery. I think that it is a normal behaviour.

You know...I'm beginning to think you guys are right (at least I hope so).
I'll update this post next when I get back my module from the UK and reconnect the battery again.

Jun 5th, 2020, 17:48	#1
anacortesian Junior Member Last Online: Dec 6th, 2022 22:16 Join Date: Jun 2020 Location: California	Buzzing sound after replacing battery I bought a 2009 C30 (2.5L Geartronic) 6 months ago from a private party with low mileage. The car just had it's 60,000 inspection at the dealer a month earlier and the only issue advised was low cranking amps on an older battery. The car started and ran fine so I put off replacing the battery for a later date. Then about two weeks ago the battery finally dies. Understandable. Luckily it died while the car is parked in my garage. So there was no towing or jump starting...I simply went out and bought a decent new battery and replaced it myself in the garage. Remembering to remove the negative terminal first as well. The weird thing is with the positive cable connected first and the negative cable then being attached (which I believe is the correct procedure)...there was this rather loud and distinct "buzzing" sound seemingly at about the middle of the engine bay...as if some relay berried there were going crazy for a few seconds...then it stopped. The car started and ran fine (though the next day there was a urgent warning seat bag light on the dash which I am dealing with and assuming to be an unrelated issue from what I have been learning about that code CFFF...and which could be caused by any number of other issues) Anyone has had this "buzzing relay sound" issue after replacing a battery?

Jun 5th, 2020, 20:54	#2
KevMan2015 Junior Member Last Online: Mar 29th, 2024 08:26 Join Date: Jan 2015 Location: Durham	Hello again, is this buzzing constant? Does it only happen when ignition is put on? After engine has stopped? Engine running?

Jun 6th, 2020, 07:20	#4
ukojesita Junior Member Last Online: Apr 4th, 2024 20:55 Join Date: Jul 2011 Location: London	My V50 makes a buzzing sound, for about 3 seconds, every time I reconnect the battery. I think that it is a normal behaviour.

Jun 6th, 2020, 10:56	#5
KevMan2015 Junior Member Last Online: Mar 29th, 2024 08:26 Join Date: Jan 2015 Location: Durham	It could possibly be the EGR valve actuating the flap really quickly to clean any carbon/soot etc. If it’s not happening all the time I wouldn’t be too worried about it.

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