Alarm fault 2009 LE 500 TF

davidgv1 wrote: I think that G0RSK is correct, (again) .......

Hi all, I have hopefully sorted this alarm problem. I warned our neighbours there was an alarm test going on and refitted the fuse, shut the garage door and left well alone for 30 mins. The alarm sounded for 30 seconds then silent for 5 secs. this sequence carried on for a while and eventually stopped. It says in the instruction book this will happen but does`nt give this as a cure for the problem. Its been 24 hours since I did this and so far all is silent.Thanks for all the advice and perhaps this info will help anyone with a similar problem. Regards John.

The alarm will only sound five times unless it is retriggered.
It is a Thatcham requirement.

I too have had recurrent alarm problems on my 2009 TF. First, the alarm would sound on starting the car, and occasionally when it was parked. This appeared to be because of a largely dead battery, as the problem went away after a battery change even though (due to a knee operation) the car was not used for the next 4 weeks or so. Now the problem repeats itself, perhaps because the car is not getting much use. The fuse is now pulled, but I plan to use the car tomorrow. I assume the alarm will sound as soon as I insert the fuse, so have armed myself with suitable ear defenders. Does anyone know what the best course of action then is to get the alarm to stop, or will it stop by itself?

I managed to sort my alarm issue out, it kept going off on its own, in the end I removed the bonnet open switch and cleaned the contacts and switch body. Not had a problem since, the switch may have had a low enough resistance to trigger the alarm by making the SCU think the bonnet was open when the car was locked.

Sundance

To my surprise the alarm stayed quiet when I put the fuse back.
Decent 10 mile run each way (essential drive because that was the nearest supermarket with any click/collect slots). Assumed that would sort it. Even locked the car just using the key based on advice that this reduced which sensors would be activated. 6 hours later the alarm sounds... Fuse out again. So will start to investigate the switches.

Although, frankly, disabling the alarm might be the best solution. Has anyone tried this? (these later cars have an alarm separate from the horn)

GN09MGU wrote: ......Has anyone tried this? (these later cars have an alarm separate from the horn)

The ZS and ZR suffer from water ingress to the alarm sounder so it might be worth opening it up and drying it out.

An update.... Second time I tried re-inserting the fuse the alarm sounded but was OK once I had started the car. Third time similar, but then everything went wrong - immobilized, windows not working, indicators flashing. Eventually managed to get it started and back to the parking spot. Fuse out again.

I am now about to remove the SCU and sent it to Technozen. I would be grateful for a few tips:
- I should disconnect the battery first, according to the workshop manual. Should I leave it like that or reconnect whilst the SCU is missing?
- is there a preferred sequence on re-inserting the SCU (battery disconnect??? alarm fuse in first or after????)

I need to avoid triggering the alarm (or it triggering itself) - not only whilst I am working on the car, but also whilst the SCU is away. I park for free in a spot outside a near-neighbours house, so need to keep on good terms with them...

Meantime, I noticed the under-bonnet light did not come on. That was fixed simply by replacing the switch mounting screw - presumably not earthing through the old screw.

You can see what all the switch inputs to the Pektron are doing with a suitable diagnostic tool.

GN09MGU wrote: ….I am now about to remove the SCU and sent it to Technozen. . .

Disconnect the battery and leave it disconnected until after the SCU is reinstalled.
Use the key to lock the car.
The alarm shouldn't sound as it is controlled by the SCU.