Engine light on / alarm systems goes off

robsm1th

Member
Hi looking for some help.

I have a 55 Z4 - owned it three years - very low mileage.

1. The engine light is permanently on. It's been taken to a bmw garage for an MOT (& passed) with only a warning that the catalyptic converter is on the way out but isn't a must fix yet. It's also been taken to a local garage who ran it through their diagnostic device and who found nothing to be wrong with it (not even the cat). Both garages re-set the electronics and light stayed out for a few weeks but comes back on again eventually.

2. Often (not every day - maybe every 3rd day or so) the car alarm goes off for no obvious reason. It's weirdly always about the same time of night (11.00 / 11.30 so luckily before bed time). An unlock of the door and a re-lock 'fixes' it temporarily.

I'm assuming the cat being faulty is something to do with the car alarm going off but I might be wrong (I know fjldkjflkj all about cars to be honest - I'm a petrol & water man when it comes to cars).

My questions are ......

1. why is the car alarm going off for no reason and

2. how the heck do I fix it when even garages seem unable to fix it for more than a few weeks?

A third question:

3. my old G reg Mazda MX5 didn't have a catalyptic converter thingy and it didn't seem to be a problem for the car (or me). Can the cat be bypassed to avoid having to buy a new one every five years or so?

The whole cat conv seems a backwards step to me but maybe the bmw have some sensible reason for installing it that isn't obvious?
 
Hi Rob, you better post your issues in problems section of the forum, which you will most definitely get more responses.

I read somewhere on the forum the other day about the alarm and the issue was the bonnet sensor, do a quick search.

hopefully you get everything sorted :)
 
2nd the bonnet catch, they can go faulty,causing "false alarms".
As for the Cat,it can be by-passed,with a cat-replacement pipe,but may then fail mot's,seeing as it will have a set emmissions limit which it wont meet??
Cats should last ALOT longer than just 5 years though. One of my old cars (which i owned new,for 4yrs) is still running around locally,with original cat,and its a 1998 Fiat Bravo :thumbsup:
 
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