ECU Battery and button replacement

[Astontony]

I recently purchased a replacement plastic "Valet" ecu from Astonbits for around $120 as the rubber buttons on mine were disgusting and moving around within the key. The new key arrived so I split the old one with a thin edged screwdriver and swapped the case and buttons and put the old innards in the new case.
I went and tested the new fob and yep it worked fine, doors unlocked, boot unlocked everything was great.... until I tried to start the car, I pushed the new fob with old innards into the ECU slot it all responded with Power beauty soul etc but would not start, I tried 3 or four times.
After many minutes trying to work out why I cracked the solution..

In the back section of the ECU there is what looks like a little 1 cm by 1/2cm rubber rectangular piece that sits in the back lid that isn't attached to any battery or has no contact with the innards of the fob ie the printed circuit board so it is easy to overlook. This is the magical little rolling code piece that talks to the car.

What I did was used the new front with new buttons put the old printed circuit in as before but this time I put the old ECU backing on squeezed it together and Bobs your uncle... it works like a charm, no re programming car started as usual so now I have a new ECU with an old backing.


Thought I would share this in case other made the same mistake in thinking that the little rubber looking bit was superfluous.

[shuzzy]

I went through the exact same process as you and concluded in almost the same way. I took out the little chip and transferred it over into the 'new' casing. Everything then worked as it should.