Clio 2.0l sport possible immobiliser issue

[gudgeon]

Hi guys,ive got a 2004 clio 2.0l sport with a non start problem,the immobiliser light is on solid and the engine only turns over on the starter motor occasionaly and then only for a few seconds but doesnt attempt to fire up at all,ive noticed the fuel pump doesnt run either and suspect its an immobiliser issue also despite trying a couple of differant diagnostic machines im unable to communicate with the ecu,can any of you guys shed any light on this problem please ?

[MicKPM]

Warning light is on solid as there's a connection problem on the core system that the vehicle needs to run.

The fact you cannot connect to the ECM says its either a power, earth or Can H or L fault so start looking for broken wires and condition of main feeds to the ECM

Mick
Diamond Motors

[gudgeon]

Thanks for the reply Mick,ive checked for broken wires by stripping the loom back over the top of the gearbox where apparantly the common fault with broken wires lies but cant find anything at all,ive checked for earth's at ecu and also live supplies but again cant find anything adrift but to be honest i cant find an ecu pin out diagram for this particular model so im not 100% sure on this,ive also checked the big white block connector and the relays on the inner wing but all seem ok,ive been in the motor trade for years Mick but this can bus stuff is going over my head to be honest lol....Thanks for trying to help me Mick its much appreciated

[Jonny1*2]

It could be a break anywhere in the CAN wires. How have you checked? It might not be visual. Try checking continuity on all 4 of them. It will be engine loom related. Manually earth the ecu/loom to rule that out.

[MicKPM]

No worries and you aren't alone as loads of people seem to struggle with CAN... If you need a hand pop it in and I'll take a look for you.

Mick

[MicKPM]

Continuity isn't always a fool proof test either. You could have two or three strands intact which will pass a continuity test but will not pass a decent signal test.

[Jonny1*2]

True. I forget the name of the kit which tests wires more accurately.

[gudgeon]

Yes ive traced the fairly thick white and violet wires(twisted pair)from the ecu and they end up at the throttle actuctor motor,ive checked these for continuity which is ok but as you guys say there might be continuity through just one strand of wire so thats not really eliminating them,ive also checked the other thinner twisted pair from the ecu and they come through the bulkhead and end up at the uch

[gudgeon]

Jonny id like to know what that piece of kit is ur talking about buddy

[Jonny1*2]

There are thin twisted white/violet wires also.

[Jonny1*2]

Jonny id like to know what that piece of kit is ur talking about buddy

It's a can-bus testing thing. Can't remember the name sorry mate. Mick will know

[gudgeon]

yea Jonny those thinner twisted pair come from the ecu and go to the uch unit i think bud

[gudgeon]

This can bus stuff is a nightmare mate isnt it lmao

[gudgeon]

Mick ive also noticed that the engine management light to the right side of the dashboard doesnt illuminate either and yet there appears to be another "engine management light"in the centre of the dash that lights up red for a few seconds every time the key is cycled ???

[MicKPM]

The squiggly line light is the electronic fault MIL. The one shaped like an engine type scenario thing is the EM light.

Check the three blade fuses in the engine bay fuse box are intact (I think it's the 15A for the ECM power) and you'll need to confirm the ECM has x2 power and x4 earths.

If you search these boards BMH posted links to a good ph2 172/182 pin out which will be handy.

Mick

[gudgeon]

Yes Mick the squiggly line light lights up and goes out after a few seconds and so does the engine management one next to it but this one lights up red,but whats really confusing me is if you hold in the end of the right hand stalk switch to do a test on the clocks and dash there is another identical engine management light on the far right hand side of the dash display that light up during this test but it doesnt light up during normal operation ???

[MicKPM]

The red engine with STOP?

If so that'll be a level 2 fault... Mostly likely due to an open circuit so back you go again to check for damaged/broken wires and faulty relays.

Mick

[gudgeon]

Ok Mick,ive got that wiring diagram off here now so im gonna have another browse at it when i get back to work on Tuesday....Thanks buddy i appreciate you trying to help me

[gudgeon]

Hi Mick,just to let you know ive sorted the problem now,you were right i had lost a power supply to the ECU,checked the under bonnet fuse (5amp)as you suggested and it was all ok,i had got a power supply to it(12v) and when the fuse was fitted also power coming out of it (12V),however when i checked the other end of this wire at terminal 30 of the ECU the wire was dead,i stripped back the loom and found a break in the wire,thanks a lot for your help with this and i hope this thread might be of value to someone else with this problem....Cheers Mick