C5 Immobiliser

[stimpy]

hi. my c5 wont start , engine turns over but the yellow key light on dash lights up when trying to start. all was fine till i disconnected battery and unplugged fuse box and comp module so i could get access to replace brake pipe

after reconnecting car spluttered a bit when pressing pedal ran for about 5 miles then cut out

all dash lights go out as normal (sometimes airbag light might stay on but thats always done that)

changed fusebox and lift pump in tank but no change

 

 

Already tried reset procedures found on net

 

[paul.h]

It seems that maybe the key is not being recognised, you could try the spare but maybe there is a wiring or connection problem from the previous work or possibly if the battery was disconnected too quickly before the bsi shutdown, then the ecu was affected (there is a battery disconnection procedure in the C5 Technical section Common Problems pinned topic). You have tried bsi resets, so have a look at the wiring/connections but then it may need a dealer visit for an immobilser diagnostic.

[coastline taxis]

remove each multiplug and see if you have bent any of the pins on the ecu also check like paul says all plugs and wires are located correctley

[MikeLane]

If the car ran for 5 miles before cutting out it sounds (to me) as though one of the connectors to the parts you removed has rattled loose. Make sure they're all well pushed home, then do the full BSI reset. Otherwise.......

Edited August 20, 2016 by MikeLane

[stimpy]

hi thanks for quick replies, key reseting sounds most likely but when i got the car last year i tried connecting 2 of them reader gizmos just to see if any probs but both devices say cannot connect to vehicle but has been very reliable till now, so maybe not poss to reset keys

ive since noticed that after turning on and all check lights go out abd  a bearly audible high pitch squeal comes from around the dash (very quiet)

[stimpy]

ive had diagnostic check done and there is no power going to the ecu , does anyone know which wire or wires on the plug are the power sources

ive cleaned all the plugs with cotact cleaner but no joy as yet

[stimpy]

during reset procedure is it normal for headlamps to come on?

[coastline taxis]

If there was no power to your ecu then your car woulnt run as the . Check all your fuses again including the maxi fuses

[paul.h]

I wonder how this ended ? When I have had a flat battery the headlights come on as well as the wipers moving when trying to start the car, but the key symbol has not shown.