Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Key transponder issue

Hannes I’m not familiar with Sigma but believe it might use the Ford embedded PATS 2 immobiliser just like the Duratec. If so I would suggest cleaning fuse number 7 (of 8).

On the Duratec fuse 7 is a heavy 20amp fuse that keeps the ecu memoray alive and the immobilser awake when the ignition is off. The current draw is minute at sub 10mA so the big fuse might just be in need of a scrub up. Worth a shot maybe…. Good luck anyway.

They told me the new transponder reads the key (same way as the old did) and transfers the data to the car electronics, therefore no new programming as the immobilizing is not in the transponder ring or key but in the car system.
Therefore dismantling the ring does not help against immobilizing.
So I was told. If it is true, I don't know

Actually that makes a lot of sense. The Ford EEC4 system was like that but I lost product knowledge after that as I moved on to Volvo Guard systems when we developed our own.

If the transponder is just a conduit between the key chip and the immobiliser unit then yes everything you have been told makes sense. Fingers crossed it’s sorted for you soon.

BR
Colin

Just to close this case:

The car was at the Morgan service station.
Back to normal now. An electrical relais was out of function.
No further details disclosed as the mechanic had his lunch brake when I collected the car.

Thanks for the update. Info now in memory bank.
Glad car is ok

I did an unexpected field test this morning. I needed the ignition key in place to turn the steering.

The immobiliser went off immediately, and with the key in place does two flash, then one longer flash every 30 seconds or so.

When I eventually came to start up, there wasn't enough in the battery.

What this tells me is that the immobiliser isn't voltage sensitive, it's temperature sensitive. Now its warm it functions reliably.

I experienced this issue with the ignition key in place failing to activate the immobiliser and the LED dash light remained flashing.

The sensor ring was moved closer to the end of the lock barrel and this worked initially. However, after a few months the issue returned. Eventually the hole in the plastic cowl was enlarged such that the ignition key almost touches the sensor ring. This worked and the flashing LED has been immediately extinguished on insertion of the ignition key every time for the last 6 months.

Of concern is what happens should this issue resurface. I am not convinced the root cause is the proximity of the sensor to the ignition key. There was a suggestion on here some ago that the wiring and/or connections between sensor and immobiliser may be defective.

Silly question but, not wanting to dismantle unnecessarily, can anyone point me in the direction of the immobiliser in order to check on the condition of the wiring?

I know this has been said. But on my 2011 4/4 I had an intermittent manifestation of the same problem. I then tried using the 2nd key. Well over a year now and so far no reoccurrence. I wonder if some keys are “weaker” than others.

Chris, on my 2018 +4 there is a black box is mounted high up behind the dash which I think is what takes the signal from the loop and decodes it. Has been produced for Morgan by a company called Avonwood Developments Ltd