Clio 182 wont start

[BennMurray]

Basically my car was running and starting perfect and then once it had been parked up and I went to start it up again nothing happens.
When I go to turn to the car over, the immobiliser light illuminates and remains in a solid red state - forcing the engine not to turn over and all that can be heard are electrical noises coming inside the engine bay and from the UCH module in the passenger side footwell.
I've made several attempts of trying to get rid of the solid red light after searching the web for some guides (leaving the key in the ignition for so long, holding the central locking button whilst turning the key, etc). But none of them have seemed to work. However, I had managed to lose the red light a few times which I had thought had solved the problem, but as soon as I went to turn the engine over all I could hear was a 'click' and then once I would try it again the solid red light would re-appear.

I have done the following to try and resolve the problem;
- Replaced batteries in key fobs
- Tried it with the spare key (with new battery)
- Cleaned the TDC sensor
- Checked the fuses both in the dashboard and under the bonnet (none blown)
- Checked the condition of the relay pins for any corrosion and swapped them around
- Replaced the battery with a new one
- Checked the condition and cleaned all of the earth straps (3 of them) under the bonnet

I'm not sure where to take it from here, any help would be greatly appreciated!

 

[littlebarnes]

i have 100% same symptoms as you...tried to start sunday and havent found a solution...have you found a fix yet or still the same?

 

[cs_dave]

Test earth from battery to body theres also the relay swap you could try

 

[littlebarnes]

thanks but still no luck, getting a new crank sensor tomorrow. and for some reason my obd reader wont link!

 

[l33th3tr33]

Try swapping the two black relays around in the engine bay fuse box. Another thing to do is open up the loom from the ecu and trace the twisted white and purple wires down to where they take a 90 degree turn and look for a possible break in the wire along the way. Mine is temperamental at the minute but normally turning the key off and on again sorts it, touch wood!
Also check the connections for anything to do with the uch.

 

[BennMurray]

I replaced the earth strap coming from the gearbox to the car body and that solved the problem.

 

[mad in general]

thanks but still no luck, getting a new crank sensor tomorrow. and for some reason my obd reader wont link!

Did you ever get a solution to this as my obd reader won't link either

 

[littlebarnes]

Yes I did. I changed the whole wiring harness in engine bay. £35 second hand of eBay. And 4 hours. Car started first time and been fine

 

[Kevlaa]

Thinking I might do the same and just change the whole wiring loom as I also have the same problem. Was it an easy enough job. Doesn't look overcomplicated I would be tempted just to hand rail each bit of wiring until the old had been replaced by the new one.