Immobiliser Issue

[ScottL]

Hi all, sorry for the long post, have done a search but can't find anything related to the problems I'm having

I've got a issue with the immobiliser on the clio, last Monday the key started playing up and I was getting the flashing red light on the dash and the car wouldn't turn over at all. If I kept turning the ignition on and of I would then get the solid red light on the dash and the car would turn over for a few seconds and stop, eventually it fire up and off I went until I parked up and I'd have to go through the whole process again.

It got to Friday, parked up at the house and went back out a few hours later and it won't fire up at all now, all I get is the flashing red light when the ignition is on. Don't have a spare key for the car so can't try that.

I bit the bullet and went to local scrapyard and bought a UCH, ECU, Decoder ring, Ignition Barrel and key.

I've fitted all these onto the car and I'm still getting a flashing red light with ignition on.

I've checked the relays in the engine bay cleaned them all up, checked the wiring to the relays. No blown fuses in the fuse box or engine bay, earth straps are ok and still nothing. Have tried all the reset tricks to try and get it to work

My car is a 51 Reg Dynamique and the donar car was a Y Reg Dynamique

The UCH's are UCH-BG from both cars and absolutely nothing

Apart from plugging it into a diagnostic does anyone else have any ideas? Is there any specific place in the wiring loom to check?

If all else fails I'm going to chuck a mallet at it.

Thanks I'm advance
Scott

 

[ScottL]

Anyone?

 

[largespiced]

Hello Mate. I had these exact same problems, cured with a new key from Renault.

 

[Dave Hester]

Flashing red light is cos the immo is not recognising the key, its maybe the key or the decoder ring in the ignition barrel. Try squeezing the button on the fob slightly when turning the engine over

 

[ScottL]

Thanks for the replays guys, tried the above and it's still a no go I've listed the ECU & UCH numbers below

Off my car:

UCH:
ECU: View attachment 88014

 

[ScottL]

Oops here's the pics:

ECU & UCH & Key off my car

View attachment 88015
View attachment 88016
View attachment 88019

ECU & UCH & Key off the donar car

View attachment 88017
View attachment 88018
View attachment 88020

Will the ECU & UCH off the donar car work on my car?

Thanks
Scott

 

[Cliocrone]

Hi mate, ive had the same trouble with my Y reg Dynamique, Try holding the Central locking button (next to the hazard button) whilst turning the key. That seems to do the trick with mine.

 

[ScottL]

Thanks for the reply but I've tried that too and still no joy with it

 

[MicKPM]

LoL I love hearing home grown immobiliser bypass processes.

If you are sure the new matches set is still doing the exact same thing as your original then you need to check the wiring. Start with the decoder as its three wires:

Red - +5v
Black - Earth
Brown - Coded line to UCH

Check for power and earth first of all and report back.

Mick

 

[ScottL]

LoL I love hearing home grown immobiliser bypass processes.

If you are sure the new matches set is still doing the exact same thing as your original then you need to check the wiring. Start with the decoder as its three wires:

Red - +5v
Black - Earth
Brown - Coded line to UCH

Check for power and earth first of all and report back.

Mick

Hi Mick thanks or the reply,

I've only got a continuity tester at the min so tried that, if all is ok the tester should give me a beeping sound but putting the red on the +5v and black on the earth there's no beep from the tester, I won't be able to get a volt tester until tomorrow to check volts ect

Hope this makes sense lol

Cheers
Scott

 

[MicKPM]

Okay, I'm with you. Whilst you're there (at the car I mean) pull the fuse for the IMOB/UCH... I think its a 5A and make sure that's intact.

Mick

 

[ScottL]

Hi Mick

I've just checked the only 5amp fuse in the fuse box, slot number 21 and it has blew. I've got no 5amp fuses at the min does it have to be a 5amp fuse or could I use a 10amp use for the meantime?

Thanks
Scott

 

[ScottL]

Mick,

If replacing the 5amp doesn't work what would be the next thing to start looking for broken wire in the loom? Could you tell me what colours they would be as I know they will be twisted around each other and the only ones that are twisted are purple and white, are there the correct ones?

Cheers
Scott

 

[MicKPM]

Replace that fuse, there's your problem and NO... Do not replace it with a higher rated fuse!

 

[ScottL]

Hi Mick, Ive put a new 5amp fuse in and im still getting the flashing immob light. Any other ideas? Thanks Scott

 

[MicKPM]

Lock it, unlock it and try again (this is the Renault equivalent of turning a computer off and on again).

If its still failing, check your new fuse hasn't blown, then if it hasn't check one side of the fuse has power.

Mick

 

[ScottL]

Mick,

Tried the unlock & lock several times and still no joy, fuse is fine and have power on one side of fuse but still have the flashing light.

Cheers
Scott

 

[MicKPM]

Okay, then now we need to check the UCH-Decoder ring signal line is continuous. If its not then the UCH isn't going to get the keys code. If the line is continuous the the key itself is most likely at fault.

You can try a second hand decoder ring if you like to but don't pay too much for one as they're not commonly failing parts.

Mick

 

[ScottL]

Hi Mick

I picked up a decoder ring with the new ECU & UCH set, I've tried both of them and I've still got the same situation, is there any way to check the signal from the Decoder Ring to the UCH

Many thanks for your help
Scott

 

[ScottL]

Would it matter if the ECU off my car is IAW 5NR.C2 and the donar car was IAW 5NR2.C2?

Thanks
Scott

 

[MicKPM]

Shouldn't do no. I'd still like it plugging in to be sure but that's not gonna happen so we can only start at the beginning and work thru.

 

[ScottL]

Okay, then now we need to check the UCH-Decoder ring signal line is continuous.

Hi Mick

Forgive me if I've missed it but could you explain how to check the signal from the Decoder ring to UCH?

Thanks
Scott

 

[MicKPM]

You can't check the actual signal but you need to check the coded line's signal from the UCH to the decoder ring... The brown wire.

 

[ScottL]

Cheers Mick

Does that brown wire run from the UCH up and across the dashboard to the Decoder ring?

Thanks
Scott

 

[ScottL]

Hi All

Managed to sort it out now, turn out the continuity tester I was using was crap, ran a 12v from the battery straight to the decoder ring and the light went out. Running a 12v straight to the ring with a earth is that safe enough?

Thanks
Scott

 

[MicKPM]

It needs a fused link mate. It may also flatten your battery. I'd advise you to repair the original circuit.

Mick

 

[ScottL]

No problem Mick ill get that sorted tommorow

Cheers
Scott

 

[Flooky]

How did you get on with this in the end?

 

[Flooky]

I checked the feed on the brown wire which I have nothing. The 12v red wire is fine. So where should I look now?
Thanks, Lee

Okay, then now we need to check the UCH-Decoder ring signal line is continuous. If its not then the UCH isn't going to get the keys code. If the line is continuous the the key itself is most likely at fault.

You can try a second hand decoder ring if you like to but don't pay too much for one as they're not commonly failing parts.

Mick