Alarm/immobiliser wont stop flashing

[Steve807]

I have a 2006 807 hdi executive
I have had to replace the pump in the fuel tank and now the indicators flash very quickly (same as when alarm is triggered) for about 1 minute then reset and go off again as soon as a door is opened etc
The horn doesn’t sound with the flashing and the car starts and runs fine. If the indicators or hazzards are turned on they work as normal then go back to rapid flashing when turned off
Does anyone have any ideas?
Or does anyone know how to bypass the alarm (please feel free to pm this information as it probably not a good idea to publish on an open forum )
Any help massively appreciated as this is driving me crazy

[wheeler]

Was the battery disconnected when you done the repair?
Does the remote control lock & unlock the doors?

[Steve807]

Yes battery was disconnected and yes car locks and unlocks both remotely and with key in door

[wheeler]

Strange one, do you have Diagbox? If so you could try un programming the alarm.

Alternatively you could try disconnecting the alarm ECU, i know its fitted on the bulkhead inside the car but can remember which side if its above the pedals or behind the glove box.
Looks like this.

[Steve807]

Have located alarm ecu and even with this unplugged the lights still flash
Dont have diagnox

[wheeler]

This is an odd one, if you havent already tried this do a full BSI reset. Failing that i think you are going to need decent diagnostics like Diagbox.
Latch the drivers door catch over with a screwdriver to trick it into thinking its closed & close all other doors & bonnet.
Take the key out of the ignition & wait 3 minutes (during this 3 minutes dont open any doors or press any buttons in the car or on the remote).
After three minutes disconnect one of the battery leads (whichever is easiest with a quick release connector). Wait 1 minute with the battery disconnected then re connect the battery.
After the battery has been reconnected wait a further 3 minutes before doing anything else then switch the ignition on, wait 10 seconds then try to start the engine. You may need to re sync the remotes afterwards by switching the ignition on then pressing the lock button repeatedly for 5 seconds.

[Steve807]

Thank you i’ll try that and report back
Really appreciate your help

[Steve807]

Tried BSI reset but didn’t work….as soon as you reconnect battery the lights start flashing…..

[PaulC5]

It might not be anything to do with the alarm, when these go off it is only for about 15 seconds. When I disconnected our C5 alarm ecu the hazards would flash when the engine was running.

Have you tried to disconnect the fuel pump to see what happens - often fuel pumps run for a short while before starting so if there is something not right with the pump or its wiring it might be causing the indicators to flash at the same time. Was the fuel pump a pattern part, what if you connect to the removed pump (without installing it) ?