Alfa Romeo Forum banner

156 JTD alarm going off when key turned to mar

1360 2
Hello all, My 156 went to get a cat bypass system made up. When doing some welding they disconnected the battery and the alarm went off. Now at this point I never knew the car had an alarm fitted as the indicators do not flash when the car is opened or locked and the alarm does not beep or sound. It has also never gone off before.

Now when the car electrics are turned on before turning over the engine, the alarm sounds for about 30 seconds or so and the indicators flash. But still when the car is locked or opened they do not flash. The engine can be started and the key fob can be used to open the doors and lock them. The alarm will not sound when the doors are opened. Only when the electrics are switched on. Is there a need to reset the alarm to the key or even to set it into a permanent disabled mode? Although seeing as there is an alarm fitted I would ideally liked to have it in a normal operation.

I have seen online a post saying press and hold the door lock button for 80 seconds to disable the alarm but this did not work. I also seen ones saying press and hold for 4 seconds to turn off the alarm before turning the key to mar. But it does not seem to respond to the key fob at all. The light on the dash just stays flashing every second or there about's.
Anyone have any thoughts?

Car spec: 03 pre face lift 156 1.9JTD 8v
1 - 3 of 3 Posts

5 Posts
Discussion Starter · #2 ·
Just an update on this, so to go over it again, the battery was disconnected and the alarm started to go off. Then after this the alarm would go off when the car electrics where switched on. But the car would function ok so the key was working ok with the immobilizer.

After going through many sites. I found some things to try. Turns out the first one, was the one that worked.
While in the car with the door shut. I put the key in and turned the car to Mar till the code light went off and then turned it off. I done this about 10 times as I found different sites giving different amounts in quick succession. Then with the key in the barrel and the electrics off. I pressed the door button. Locking the doors. I then pressed it again to unlock them and turned the car to mar. The alarm did not go off.

I got out of the car and locked it and left it for 5 min. Then tried opening the door and starting the car. The alarm is no longer going off.
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.