I am seeing more failures in the TRW(ex-Lucas) immobiliser on the MK2.5 cars. These are not available new and it is not possible to reprogram a used immobiliser from another car. Up until now the solution was the same as for a water or otherwise damaged ecu which is to replace all associated components with those from another similar car. Given the rarity of some of the ecu sets and an increasing incidence of immobiliser failure we have developed an emulator to replace the faulty immobiliser.
If your car suddenly becomes a non start and stays that way, it is likely that the faulty component, if from the ecu/immobiliser system will be the ecu. If the car fails to start uncharacteristically on one occasion and perhaps months pass before this occurs again but there is an increasingly recurrent intermittent fault, the immobiliser is likely to blame. In any event always check the ecu for obvious corrosion. Remove the connector plugs and ensure that all connector pins on the ecu are shiny and clean metal. Take the back plate off the ecu(4 philips screws) and visually check as well as doing a sniff test for a possible electrical spike issue(rare on MK2.5).
We require the TRW immobiliser unit and a transponder key from the car. The key is required to test the immobiliser in a harness and confirm fault before progressing. Once fault confirmed, the main chip is then removed from the immobiliser and data read from it and programmed into the emulator replacement. The newly programmed emulator simply plugs into the car, replacing the immobiliser and will resolve any immobiliser issue.
Assuming the incidence of original immobiliser failure continues to increase on these cars, the availability of an immobiliser emulator will future proof this function.
So the new box you will be re programming is a direct replacement for the Lucas box?, but in most cases it can be down to a faulty ECU, is it not worth sending the full system to check before programming a new box in? IE:- key,ECU, Immobiliser box, that way it does not waste your time and costs and the owners if you find out it is not the immobilser at fault.
Out of interest can you program the box to make it unimmobilised so either a after maket system can be fitted or for a track car.
Given your initiative/knowledge, the fact your ecu set is the most common one available and the price I know you paid, you did the right thing and ended up with other valuable parts as well.
May be worth keeping the old set though as it is potentially of some use.
This system is really going to be useful for the rarer ecu sets and if/when we reach a crisis point with failing immobiliser boxes.
Up until about 18 months ago all problems I encountered when diagnosis occured were down to failed ecu and/or connector plugs, usually water damage.
Aside from customer issues with failed immobilisers on the MK2.5, I have had one of mine fail whilst in dry storage and another fail a week after installation.
You are right - most failures with all these MK1 - MK2.5 from my experience are water damaged ecu. Yet to have proven ecu failure where water damage or on rare occasions electrical spike not responsible. It seems that the actual components on these ecus are not failing at the moment without external cause. Fortunately, for diagnosis purposes, in most cases ecu damage stops the car dead and produces very obvious evidence, hence the requirement to check before going the emulator route. The clue to most immobiliser faults I have encountered is the intermittent nature of the fault. Apparently it is the main chip that starts to fail and when removed evidence of moisture ingress seems to be the probable cause. ECU failure may be progressive in its nature but not known an intermittent start. When corrosion/electrical damage on the ecu stops the car that is the end.
The emulator does directly replace the immobiliser but its function is simplified. It holds sufficient data, PIN, key, etc to effectively communicate with the ecu allowing the car to function normally. The immobiliser security function ceases as does the requirement for an antenna or transponder chip. It basically works in the same way as the demob style of ecu/immob replacement with which I am sure you are familiar. Getting rid of the immobiliser function completely is not possible as far as I know. Stock ECU function will always rely on communication with an associated immobiliser or immobiliser emulator. Because of the way the emulator functions I would expect an aftermarket immobiliser/alarm could be fitted. Fitting a programmable Megasquirt/ME221 does away with the immobiliser function on MK1/MK2, reasonably sure they are also available and do the same on the MK2.5.
The test harness can also check ecu function but given the expected intermittent start issue and a clean ecu, wiring , pins and connectors, sending just the dead or deadish immobiliser and a key with transponder that will no longer be required is the current recommendation. Proving an immobiliser fault is the key to this. If the immobiliser is proven working or the emulator fails to cure the cars starting issue completely we make a charge but refund as much money as reasonable. The emulator can be reused for another car.
There is some issue with the obvious loss of immobiliser function in practical terms. From my experience where a seamless solution for MK2.5 ecu/immob failure with two chipped keys is available for a little extra money, 90% of owners go for the cheaper and more convenient demob solution. Having said that I have a plan to develop a direct replacement for the MK2.5 TRW immobiliser with full functionality.
Hi I am having issues with my car it won’t start and ecu/immobiliser has been tested and immobiliser is to blame on a year 2000,
do you still do your fix. Ifso please let me know what you require.
Thanks
Hello, My immobiliser failed during my MOT causing the mechanic Simon to panic saying I just turned it off honestly. So if this emulator fix is available I would be very grateful if you could tell me where to send it and what it will cost as I don’t really want to put another old immobiliser in it that is probably on borrowed time anyway.
Hello, I understand your point, although Simon should not really be panicking. It’s a well known problem with the MK2.5 immobiliser; you know about it. He should possibly know that disconnecting power or the immobiliser momentarily will probably reset it for one start.
The sad truth of this matter is that the emulator has not been available for some time. Unfortunately it seems that the auto electrician who developed it with me has some kind of issue. His own mainly redundant website says returning on January 15th. No highly qualified auto electrician with knowledge/access/control of emulator pic code on board = no emulator!
Only one good thing to come out of this, his wife, bless her, sent all my development parts back and also a MK2.5 test harness. I have developed the harness such that now possible to fully test transponder/immobiliser/ecu compatability and operation and now program transponder chips to all relevant MX5 cars, MK1 1.8, MK2 and MK2.5. Strangely the only one I cannot test or program on the harness is the MK1 1.6 = my car!
Given that there is no emulator available, the only viable option I am aware of is to replace the immobiliser and associated components. As you correctly state, this is not a great option as all these units are effectively on borrowed time. For my own part I now offer a three month guarantee with the MK2.5 ecu sets I sell to take some responsibility for this unfortunate situation.
I did send you a private message; perhaps you haven’t seen it?
Hi sorry I got the message but It is my wife’s birthday and so I have been panic buying and wrapping presents the last few days. But she is now with her friends in the back garden drinking, so I can have five minutes to respond. I will have to replace the bits or stick the car on the wall of the garage because it is just a paperweight at the moment.
Could this be a problem with my 2001 mx5? It’s a rocketeer conversion with an MBE ecu and I’m not sure if there is a separate immobiliser box/ecu. Symptoms are the starter motor won’t spin up, dash lights are as normal, happens randomly about once a month, when it won’t start I’ll try again a few seconds later and it does start.
An interesting discussion wrt immobilisers etc but I am not a mechanic by any means (and neither is my son). My son has a MK 2 (02) plate and since bringing it off SORN for the summer has had an issue where he cannot start his MX unless he removes the negative terminal of his battery, briefly touches it to the positive terminal and then his car will start first time! If, when he turns the ignition off and leaves the key in place it will start every time!! If he removes the key and re-insert it he needs to disconnect the battery again. He has had an auto elcetrician look at the system and with his test equipment told my son that the problem was the Ignition Switch Transponder Ring not recognising his key. He left him stating that he would let him know what to purchase and then would come and fit it for him as well as telling him about the battery negative disconnect process. Since then he has had no replies or response to any of his numerous telephone calls and is becoming rather upset about it all. He says that he has seen the ring he requires on Ebay and has had a look see if he can replace it himself but the question here is, is this transponder ring a ‘plug and play’ or does it need some form of programming to match the keys? Neither of us are mechanics as stated above so we either want a simple solution or a positive statement then we can maybe see about someone else having a look. He lives in Suffolk and I am in Hereford! Help please!
If it’s a 2002, the car is a Mk2.5 and therefore very likely an immobiliser issue.
Disconnecting battery/immobiliser resets and often facilitates one start.
I will send you a private message.
Rob, I have sent your responses with the link to my son.
I hope that when he sees your link page he will act accordingly.
I do believe that he was definately told it was a Mk2 as he doesn’t have central locking which he believe came with the Mk2.5? I could of course be wrong!!!
I am very pleased to confirm that we are now in a position to supply an emulator for the MX5 MK2.5 again. It has taken quite a while to find the right partner to work with this time after the very disappointing departure of my original development associate. We have started completely from scratch with this and after recent testing on a MK2.5 on my drive have produced a working emulator.
The MX5 MK2.5 emulator replaces the failing immobilisers on the MX5 MK2.5 as well as the transponder chip requirement. When fitted the emulator works with the ecu in the same way that the key contained transponder chip and immobiliser did. You will just need a metal key to operate the ignition to start the car.
Essentially this part can be supplied with minimal information, supplied by email. It will be guaranteed to work and will have a limited one year warranty. Your ECU will not be interfered with and none of your parts are required. I can basically supply a part that will work out of the box. If, after discussion, the car issue is not immobiliser related and the emulator not required for future proofing your MK2.5, a return will be accepted and money refunded less costs and a reasonable charge.
Currently only available to be fitted directly into the existing immobiliser case which is probably the best idea anyway but a bespoke case will be an option shortly.
We are also hoping to offer an emulator for the MX5 MK2, MK1 and other vehicles with a similar immobiliser process shortly.
Looking forward to my first customer.