*SOLVED* Key Fob Locks But Won't Unlock After UCH Replacement

[CamMoreRon]

Hi All,

I just replaced the UCH on my 172 Cup with a re-programmed unit from eBay (i.e. sent my old unit off to be decoded). Everything seems to work, but the key fob will only lock the car, not unlock it. If I lock the car, I have to get in by unlocking the passenger door, which sets the alarm off.

Can anyone help? I found some threads on t'interweb but nobody ever updated them with a fix.

 

[CamMoreRon]

Update - I tried to start the car yesterday but no joy.. sometimes the engine wouldn't even crank, others it would crank for a random amount of time then stop. The immobiliser light is on solid, suggesting the fault persists with the new UCH.

I cleaned the engine bay relays and this helped get consistent cranking, but the immobiliser is still staying on. I'll replace them with some new ones as a matter of course, but I think the problem lies with the UCH still.

All other body electrics seem to be working now though, whereas before nothing did. Just the unlocking and immobiliser issues remain. No fuel pump either.

I also spoke to the seller and they mentioned two things:

1 - Sometimes the UCH develops a fault when flashed and this could be the cause of the unlocking issue

2 - The part number on the one they sent is for a 1.2 so it may not be compatible.. they have an identical part to my old one, so are sending that out FOC

I'll update this next week when the new one arrives.

 

[hipwell]

Do you not need to replace the UCH along with the ECU and the decoder ring around the ignition?

 

[CamMoreRon]

Do you not need to replace the UCH along with the ECU and the decoder ring around the ignition?

The UCH has been re-coded to my old one, so should be plug & play without changing anything else. I believe this is what happens when you buy a new UCH from Renault.

 

[CamMoreRon]

Success! The replacement UCH arrived today and after swapping it out everything is working as it should!

For anyone who comes across this thread in the future: make sure you get the EXACT part number, as "UCH-N3" isn't close enough. You need the long PN starting P8200..



As a side note, I have a Bluetooth OBD2 scanner and if I read fault codes from the ECU with it this seems to knock the key / UCH / ECU synchronisation out and I need to re-sync the key. Something to look out for!

 

[White16valver]

Good info, thanks for reporting back ?