Good afternoon.

I currently have a Mitsubishi outlander 2.0D , had the car for a few months and never missed a beat, yesterday however the car alarm has decided to go completely berserk .

basically if I lock, or unlock the car using the key fob, the alarm goes off for a couple of seconds.
the car starts and drives fine, the immobilizer for some reason luckily hasn't kicked in.
however when driving, sometimes randomly the alarm comes on, and if I press the hazard lights or the left indicator that seems to trigger the alarm as well.
I've had the car in a garage hooked up to a diagnostic and no faults have come up.

I had a quick browse here but can't seem to find anything similar related so just wondering if someone with enough experience could give me some advise on the subject.
thanks In advance

 

stock alarm or aftermarket?

if stock alarm, I would look at the pins (trigger). If aftermarket, it could be the motion/prox sensor (again triggers or grounding issue). It could also be the "brain" or main module going bad. Does the car have any other electrical issues?

The alarm is typically independent from the cars onboard ODB2 diagnostics and immobilizer; it could trigger the immobilizer but they are different. The shop should have told you that before booking up the car to diagnosis an alarm issue. You should take it to an alarm shop (shops that do tint, rims/tires, alarm, etc). They can easily trace wires to find the cause. Actually, the best route, IMO, is to have a cheap aftermart alarm installed. This way, they have to disable the stock one when they install the new one; evaluate cost diff.

 

No experience, but seen it suggested to check the battery. A dying battery can cause alarms to go off at random times.