[new2rover]

My alarm had failed again, car immobilised, and endless number of hours spent on sorting it out resulted in nothing so someone I was speaking to suggested that i try someone he knows who runs a shop where he make s car keys and programmes keys and chips and transponders.

The guy runs a mobile service as well, so he offered to come over as he is not far away from me, and plugged his machines into diagnostic port and said my 5as Alarm Module is not establishing communications, he tried various things but no communications could be established, he was real nice guy and said he won't charge me as he was on his way to another job nearby. It was so nice of him. I tried to offer him a tenner but he refused.

So now, it seems that my 5as may possibly have gone wrong, so if I can get another one he may be able to programme it to my keys and possibly the ECU, though he admits he hasn't done one on a Rover as he is relatively new i to the scene and can do BMW and Mercs, Vauxhalls, Nissans and so on, but he could not tell me for sure if ECU will also need pairing with a new 5as module.

Then looking on ebay, I found lots of ECU and paired 5as modules with key fobs available for around £30-£45 for Rovers, however when i checked what my ECU was, against what was being sold on ebay, it was not the same, mine is Rover 216 sli Coupe, so looking further into ebay it became apparent that for rover 216 sli couple they are only selling ECU's alone, and no 5as alarm module or key fob, I therefore rang one seller and asked him if his ECU will work on my car, my car has a Denshigiken ECU type 37820-PP4-R50, it is one with 4 mounting s, and has an LED window, uses two ports for connecting loom, one being Green and the other Black. So I asked the seller if I order one and it doesn't pair up with my new 5as Alarm module, and fails to work or doesn't get paired, will he take it back and refund , he said yes, and started to explain to me that my ECU will not require pairing as there is no immobiliser built in my ECU, how does he know for sure?

I asked him what does he do, i.e. does he specialise in Rovers , and he said yes, he has worked for Rovers for 20 years, and has tons of experience and knowledge with regards to immobilisers and ECUs.

So now it appears my ECU does not have a built in immobiliser, that means I can look up wiring diagram in haynes manual and bypass the commands from 5as module to switch on the MAIN RELAY, which when i looked in haynes manual does fuel pump and starter motor relay and possibly ignition enabling the ecu.

Any one thinks this is not the case please let me know. Many thanks.

[GTiJohn]

Have you spoken to 'BobbyBrown' yet?

He's my 'go-to-guy'....

[new2rover]

Yes thanks John, i have contacted him, I got his number and texted him, we went through a lengthy texting, explaining to him what i have checked and observed, and at the moment I ma still figuring out if there is anything else that may be causing my problem. A friend saw me struggling with it suggested that he knows a mobile lock smith who does all kinds of car locks and programmes keys and transponders, he has plug in diagnostic equipment, he connected his £600 device to my car on its 3 pin diagnostic port in the engine bay and his equipment failed to establish communication, indicating a possible problem with my 5as Alarm module.

So I am now looking to purchase a used 5as module that I might be able to get someone to programme or pair it with my ECU, though the keys can be paired more easily, Bobby Brown is not able to programe ECU to 5as, but he can program my keys to a new 5as.

My options are if I can get all 3 things from a scrap yard for about £50- £100 as a complete working set. I also need to check my car for any broken wires in my door looms and another good chap I spoke to who does Rover MG alarms based in Brighton (Paul Brown) of Technozen Electronics had a lengthy phone call where he said tail gate loom is far more vulnerable to cables broken, I have yet to check that. But it does look like my 5as may be up the wall.

Many thanks for you help, appreciate your time.

[Mr Teddy Bear]

Assuming that you have a R8? with a 1.6 K Series transplanted into a 1.4? then the plug isn't compatible with modern systems. You need the early version of Rovers 'Test Book' diagnostic equipment to get any where.

[Mr Teddy Bear]

Sorry just read your penultimate post and I'm still confused as to what engine has been fitted into your car is it the D16 Honda, or the 1.6 K Series ? Where is the ECU ? in the engine bay or under the carpet in the passenger front seat footwell?

Certainly up to 1992 the Honda didn't incorporate a engine immobiliser into the ECU .

[new2rover]

Sorry Teddy Bear, the ECU is under the carpet in the passenger carpet covered over by a steel plate and a glass window through which you can see a red led blinking when ignition is switched on. I am not even sure if it is K series or R8 but yes the log book says 1.6l 16v single cam, it is an Sli Couple.

I have been meaning to check for any broken wires in door looms and tail gate but did not managed to find time today though the weather was not too bad, it wasn't freezing as such and to work inside a car if it is freezing is not a very kind experience.

I have also managed to find pin outs from Avon diagnostics web site instruction manual for one of their kits that describes the function of each pin in the 5as, this really can help with diagnosing wiring problem as Haynes manual shows absolutely nothing.

Reason why I think my 5as is up the wall:

assuming your key fobs were out of synch, and did not respond to buttons (locking or unlocking ) then if one was to open or close doors using the mechanical key in the door lock, 5as should then respond to commands from the door barrel switch, which in turn outputs central locking current through on board relay within 5as, to open or close door locks motors, and it doesn't, so indicating either a problem with door looms wire broken or 5as gone up the wall.

Someone else also suggested that a common problem can be a broken tailgate locked (boot lamp switch) wires in the tail loom, which can possibly (not 100% sure) effect the 5as operation.

[Bobbybrown]

If you were nearer I would be keen to plug in your 5as and see what's going on with it.

I have a bench rig here that I built which is effectively a car in a box, just enough for the ECU and 5as units to communicate effectively so they can be programmed off the car, these are pretty basic in terms of the circuits that are involved.

My rig mk1 doesn't have the door lock circuits, it's basically a diagnostic plug and a 5as plug with the associated wire in between connected how it needs to be to work.

The mk2 rig has the door lock circuits so the 5as can be tested for operation after programming.

It is this reason that I can't see why your door locks would make any problems with fob synching.

It would be much easier to show you than to describe what I mean.

[new2rover]

Hi BB, another reason I suspect something is up with my module, is when a friend who suggested I call one of the local car locksmith, who has all the gadgets necessary to read and program various ecu's and keyfobs and transponders, he can also open door locks if you lost your keys with certain contraptions that most locksmiths reluctantly show how it is done, he tried 4 times two times with each of his handheld console gadget, one looked pretty complex with an LCD screen and menu, but failed to connect or communicate with my 5as module hence the reason why i have not sent you my 5as as of yet, and I see many 5as on their own going for sale for about between ten and fifteen quid, at the moment I don't want to spend my money on a wrong one as most sellers won't accept it back if bought incorrectly. So please give me a few more days and see how far I get on checking each wire to my 5as, so far I have established that a blacK wire with red tracer does connect to it that comes from door barrel switch, and it has +12v at pin 26, and that central locking wires are also making a contact (continuity) through my door loom, whether this continuity is intermittent is hard to tell at the moment.

I am not sure what pin No 3 on 5as is which is described as 3TH Diagnostic and becomes active when taken low, and function description says Square wave 250hz if 3TH ok,

and pin 12 described as 3TH Output, presumably, is the output mentioned above (250hz sq. wave out if 3TH is OK, or if Disarmed and Ign On.

what is 3TH I am not sure?

[new2rover]

Duplicated post deleted. :

[new2rover]

With everyone's help and contribution from these forums, and information resources from other websites, I managed to locate the cause of my alarm that kept going haywire, turns out in the end an intermittent broken wire in the door loom, responsible for central locking switch (this is a switch that tells alarm module if the doors are open or closed) without this switch functioning correctly the alarm module can do funny things and one gets lead away into thinking something else must be wrong with the 5as alarm module.

One could end up spending unnecessary resources on having module reprogrammed, and only to find it was nothing to do with the module itself but external wiring faults.

Glad to say I am now back in the riving seat and what amazed was that my spare set of keys did not need to be re-synronised and started to function more or less straight away, at first when I pressed its buttons, the red alarm led started to blink strangely as if something was wrong, pressed it again and locks started to go up or down, that indicated that my 5as alarm unit was responding to it. Even though I unplugged the module from the car and had it looked at.

So now i have learned a lot about this alarm, and know next time where to concentrate if there ever was another similar fault.

cheers guys for your help.