355 Siren just goes of after car is locked with FOB

I think i may have a faulty door, bonnet or hood switch? 96 GTS. Can anyone advise on where the door switches are? and do these work around window position?? I have located the bonnet and hood switches. My car locks with 1 beep and 1 flash siren goes off sometimes after about 15mins or just goes off randomly. When you turn the alarm off with the FOB it has 3 beeps and 3 flashes. Book says forced entry?? siren has new batteries about 12 months ago. Bit weird but I'm sure someone will have the answer. This isn't something crazy like a blown bulb is it??

 

Paul, the door switches are where the bottom hinge of the door is. They are hard to see if the door is not fully open. They are mounted on door frame. Give them a shot of electrical spray (not WD40... something like isopropyl alcohol to flush out contaminants.

Does your interior light work properly when you open and close the door?

I get confused what part of the door does what. I think your door won't lock if your latch switches are faulty, but if the door hinge switches are showing open after the door is locked, it triggers the alarm.

How are you checking your switches?

 

Interior light works as normal. I had my young bloke operate the FOB while I held the switch pin down. The bonnet and hood seem to working fine. I will check the door switches after work tomorrow. It must be just a contact as a number of times testing the alarm worked as the manual stated. So it's intermittent. Door locks operation is normal no issues

 

Not likely. The circuit is quite complex, however. Perhaps shorted wiring in one of the door open lights could trigger the alarm.

Have you had problems with door wiring before?

Does your car have a door open/seatbelt not latched buzzer?

 

No and No mate. Both inner door lights working.

 

Unfortunately, intermittent problems can be hard to track down, but, in this case, you can isolate faulty parts by disconnecting them. Removing the faulty parts removes the earth which triggers the alarm. The alarm is looking for earths from things like:

Door open switches (I'm not sure how you get to the wiring on these)
Luggage Compartment and engine lid switches
Courtesy lamp time delay relay (P/N 153119 located near the forward luggage compartment latch.. hard to find. It's on the right hand side latch on my RHD car).
Brake/Seat Belt/Door Open Module (P/N 137667 on Australian and Euro cars .... under the dash near the driver's knee, I recall). Disconnecting this also removes the left hand door switch from the circuit.

 

Usually caused by anti lift sensor. Can very easily be diagnosed by SD1 or 2.

 

Not really. It keeps a record of what caused the alarm to go off. Just have to diagnose it with the factory equipment, look at the report and see what component was responsible when the false alarms happened.

 

I did have the car jacked up with front wheel off to check CTEK connection.??? Suspension light was on for about 5 secs when first driven. So I need to take to a dealer to clear these alarm codes? And this has to be an SD1?

 

Here are the screens that can be viewed with the SD1


Image Unavailable, Please Login Image Unavailable, Please Login

 

What codes?

Reread post 7. It is all you need to know.

 

Brian, if it works sometimes, wouldn't this indicate that this particular problem is not being recorded? Do recorded faults retrigger the alarm or are they just held in memory for later diagnosis?

Would low battery volts cause a problem or can the system distinguish between slow discharge and the battery being cut off? Paul, was there a particular reason why you were checking the CTEK connections?

 

Anytime the alarm goes off it is logged in memory.

 

I have a code scanner but to be honest I don't know if it reads the same codes as an SD1? I reread your post and don't understand what your telling me? Yes I need to go to a dealer or no I can read with any code reader?

 

A code scanner will not read it. It wont even connect to it. You need to use an ALDL cable and connect directly to the ECU with an SD

 

Understood. What I'm trying to determine is if the logged faults are passive. If a faulty part is replaced with a serviceable part, but the codes are not cleared from the memory, does this prevent the alarm working properly (e.g. irregular lights/beeps occur during the arming process and the alarm triggers after arming?). Or is it like the suspension ECU? i.e. the ECU logs lots of faults, but in most cases, the faulty parts can be replaced and the warning light goes out. The faults remain in memory, but it doesn't affect the operation of the ECU.

 

I suspected a loose fitting after changing a stuffed stuffed battery. They were fine. It hasn't gone off again as yet? I'm suspecting a door micro switch as when disarmament of the alarm there were 3 beeps now I only have 2 beeps when disarming.

 

Hello can someone please advise on the general location of the antilift sensor and if there is just a sensor and ECU? Little bit confused with the multiple part no's

 

The sensor is a surprisingly large black cylinder, near the CD stacker (at least on my RHD '98 car). You have to remove the luggage compartment liner to get to it (side piece liner). Next generation sensors are much smaller, rectangular and lighter. It seems that the newer sensors can be retrofitted to older cars using a kit. The older parts are NLA (except on the second hand market).

The newer type seems to be a 3 piece kit:

https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/355-group/f355-m5-2-1996/electrical-boards-and-devices-front-part.html

1) a new metal (2-part?) mounting plate (item 48 on parts diagram)
2) a harness assembly (item 63)
3) the sensor (item 62)

Kit part numbers are based on whether your car is LHD or RHD. You'll need the kit P/N 180097 for your RHD car. If you already have the newer type, you may be able to buy the sensor, alone, second hand. I believe the sensor P/N is 177149 (for all cars).

 

Alarm went off again at midnight. Upset the neubours a bit bloody loud.

 

Strange, especially if your car is in a garage (unless you live next to a train line or your neighbours like slamming doors). Did you deliberately arm the alarm to test it? If your car is in a secure garage, I wouldn't bother arming the alarm. Just let the immobiliser function protect the car.

 

Good idea. very secure, no trainlines.
Still would like to get to the bottom of the issue

 

Ordered all parts for new generation sensor

 

Nice. A good weightsaving exercise (if nothing else).

How sure are you that's the fault? Did you clean and exercise the door switches?

https://www.ferrarichat.com/forum/posts/145616977/

The door switches look really difficult to replace (at least on the F348 when the wiring is too short)

https://www.ferrarichat.com/forum/threads/door-switches-160-161.561839/#post-145612044

Switch part number is 134423

Let us know how you go.

 

Yes mate tested all switch's and they all work perfectly. The newer sensor set up is the go