C30 ‘Alarm Service Required’

[Marc p]

Hi guys,

Hoping someone can give a pointer on this one to put me in the right direction.

So to keep it brief, bought a ‘13 C30 that has the ‘alarm service required’ message on the dash, previous owner(who had the car from new), informed that it appeared after a new windscreen was fitted two years ago, but never got round to sorting it as the alarm worked fine.

I’ve tested the alarm system(locked and armed car with fob, then opened it with the physical key) and it does indeed work and siren goes off loud as it should.

I know that the sirens can cause the error message but this one works fine and a bit too much of a coincidence to fail at the same time a new windscreen is fitted. So I was wondering if anyone knows of any other sensors/modules around the windscreen that could of been disturbed whilst it was being replaced? Also, just to add the sensor/light on the top of the dash seems fine as when the car is locked, it starts flashing as normal.

Thanks in advance

[595Heaven]

I wonder if it is the battery backup for the alarm sounder that is failing. Over time these, like any rechargeable battery, tend to lose their ability to hold a charge.

Either that or the internal sensor ( usually ultrasonic) has potentially been left disconnected. These tend to be in the other head console near the rear view mirror so should be easy to check

[Gary C]

A quick search suggests its the internal battery that is not holding a charge.

Thing is, its also suggested that the battery can then subsequently leak and destroy the alarm PCB.

[Marc p]

Thanks guys, I’ll check out the sensor in the roof and probably order a new battery for the siren as I know they don’t last forever anyway. I think I can be safe in thinking that the battery hasn’t leaked to destroy the PCB though as the system and siren is all still fully operational.

[Super Josh]

Had the same with Mrs SJs C30 a number of. years ago. There are two different batteries fitted into the alarm module depending upon year. I opened the alarm module to see what battery was fitted (fitted under the scuttle panel so you will need to remove the wipers first) and ordered a suitable replacement from Ebay.

Cheers,

Josh

[Marc p]

Thought I’d update this now it’s sorted. I initially replaced the battery but that didn’t work, it ended up being the alarm/siren unit itself. I have no idea what was wrong with the old one as it functioned normally and the pcb board looked fine, but after replacing the unit, the message disappeared.