1 reply to this topic

[brendan]

Hiya guys

can anyone help me

i have a touchy alalrm system, its a standard rover alarm for a 96 sidewalk. what happens occasionally is one day the alarm will work fine, i will activiate the alarm and when i next use my car and i press the unlock button on my immboliser the alarm doesnt de activate, which mean the alarm goes off when i open the door and i cant start the engine. this is very annoying as it only does it every now and again. Thing is i then deconnect the battery for 5-10 mins then reconnect and reset the immboliser and then it works, till next time! I really dont understand what it could be. I have changed the battery in the immboliser but no luck, i have also checked the wiring and nothing seems wrong, but i dont really know where to start! Any advice?


brendan

[koss]

 5as.gif   46.6K   10 downloads

The above picture is a TRW 5AS Body control module. It is fitted to Rover Mini / 100 / 200 / 400 / 25 / 45 / MGF from May 1995 to present. Earlier parts were branded Lucas rather than TRW. This unit control the cars security and other body control functions. Common failings of these units include Key fobs no longer working, and immobliser not functioning correctly. All 5ASs carry a date code on the right hand white label. Its in the form XX/YY, i.e. week number/year. 5ASs pre 1996 had an earlier RF (Radio Frequency) receiver on board. This was far more susceptible to 'jamming' from interfering radio signals than the later design. The result of this is that owners can experience apparent remote control failure in one location, but when the car is moved away from the source of interference, the system functions correctly again.

Could this be your problem?

This may be wrong but also worth a try.
Open the door with the key/alarm may sound/Turn ignition on/Leave both front doors open and disconnect the battery with the ignition on.

After 10 minutes reconnect the battery. Then turn ignition off.
This on a lot of rovers disables the immobiliser for good. But you cannot use the fob again. If you do you will be back to square one.
I use this method when people have lost or broken the fob. An after market alarm can be fitted later.
Good luck.