C5 mark 2 estate 2,0 HDI weird problem

[kevino]

Hi guys, I've a weird one for the forum. I've just replaced the radiator as the old one was leaking. To be safe i disconnected the battery and went ahead. All went well until i reconnected the battery. The indicator lights are flashing rapidly and go back to normal after about 2 minutes. I've tried syncing the remote also I've checked the battery and it's producing 12.9 volts. Has anyone had similar and how did you deal with it?
Thank you in advance

[wheeler]

Is the car starting?
You say it goes back to normal after 2 minutes? what happens then?

[kevino]

Ye it starts drives perfectly but once you stop it and lock the doors, the next time i use it the same happens again.

[wurlycorner]

Lights flashing rapidly on a c5 mk1/2 normally indicates that the alarm system thinks someone tried to enter the car/part of the car wasn’t properly secured when it was last locked.
I think there is a switch that detects the bonnet is closed and as you’ve just replaced the radiator, I wonder if you disturbed that (or the wiring to it) and it thinks the bonnet hasn’t been properly closed/has been opened while the car is locked?
Do you have access to lexia/diagbox (or another diagnostic tool) so you can check and monitor that it shows all the doors, boot, bonnet etc are showing closed, when they are?

[wheeler]

What year is it & does it have a factory alarm system?
Did you get the remotes to work again?

[kevino]

It's an 06 model with the factory fitted alarm. Remote on s working perfectly.

[kevino]

Hi wurlycorner, i thought it might be something to do with the alarm system as i had to turn the internal sensors off as the alarm was going off all the time, however i think the sensor button isn't working as the light does not come on when the key is turned but the engine not on no matter how hard i press it.
I do believe that i would have to take the stereo unit out to get to the rear of the button to test it.

[PaulC5]

Have you tried a bsi reset, just in case you originally disconnected the battery without following a procedure ie did it too quick before everything shut down ?

[kevino]

Ye, do e a bsi reset, disconnected battery, drivers window was already open, waited about 5 mins , connected battery, waited about 2 minutes then inserted key into ignition, pressed button on remote for 10 seconds and then fired the car up.
Other than the lights flashing there's nothing wrong with the car.
I think it's the alarm that's faulty.

[PaulC5]

Does the alarm work as an alarm - you could try it by unlocking a door using the key and see if it goes off when you open a door. Then to stop it put the key in the ignition and start the engine.

I think if the switch has a red light lit on it or it flashes that indicates an alarm problem which will be in the handbook. A diagnostic will likely give you any alarm faults. When checking for possible battery drainage I checked the alarm on our C5 by disconnecting the siren but it made no difference. I then disconnected the alarm module but when the engine was running the indicators kept flashing and the switch red light flashed. With just the internal sensors disconnected from the module it worked ok. None of this reduced the battery drainage though so I connected it all back.

[aspire_helen]

I agree this sounds like an alarm problem, and good diagnosis procedure (re radiator change) may point to a dicky bonnet switch (integral with the external bonnet catch). I would try alternatively shorting and opening the leads to see the effect.

However, could the alarm be more trouble than its worth on an old car, especially if the rechargeable battery in the siren module is beyond its life? Following on from PaulC5 ,,,,,,,,,,,,,,,,,,I too have been plagued by mysterious battery drain, waking up twice to a 8 to 9v battery, which I attributed to the alarm. Consequently, I dont use the alarm, but lock the car by key (thus not enabling the alarm) with the added benefit of being able to removing the deadlocks should I have to break in.....I think I have more chance of losing the key and locking myself out than having my 24 year old C5 stolen!!

In addition, I fitted the battery with an Ancell BM200 bluetooth battery monitor for £18 for remote monitoring. Brilliant piece of kit, providing battery voltage and temperature every 2 seconds and storing a month of data, plus cranking test and charging test. It also has a car location and trip recording functions when linked to a phone with GPS (although they are not that impressive).

[PaulC5]

Our C5 was kept in the garage so I often did not bother locking it but the battery would still drain so I am not sure if the alarm had anything to do with it draining.

[kevino]

Hi guys, i gave up and took it to the garage. It is the alarm box which is located high up behind the glove box. The alarm has been disconnected but the lights keep flashing. Garage says it looks like a problem with the bsi and they think that changing it might solve the problem but they can't be certain.
Question i want to ask the group is if i put a new alarm box in would this potentially fix the problem, or can the bsi be cheated into thinking the car doesn't have an alarm by putting it through a lexia.

[wurlycorner]

Honestly don’t know if that’s possible, but I doubt it.
Also I’m confused: if it is a problem with the BSI then why would it be desirable to disable the alarm anyway? Just replace/repair the BSI and have a fully working car again? What am I missing?
I’m also a little surprised why the indicators would be operating after disconnecting the Alarm, but with knowing what they have done/diagnosed in full it’s very difficult to say.

[PaulC5]

When I disconnected the alarm module on our C5 the hazards flashed whenever the engine was running. It will be a security feature and nothing to do with the bsi having a fault. On our C5 the module is located in the pillar at the left side of the glove box and was a pain to remove/put back and needed the glove box removing to help. The alarm siren is located at the rear left side and needs the boot lining removing at that side as well as at that side the bumper releasing and pulling out a bit since without there is not enough room to extract it. The bumper needs the left light removing on our estate.