No ignition

[quattronutter]

Vcds ,25- no response from immobiliser,cannot access in vcds even though it is started and running or with ign on...

[quattronutter]

Also have a 00470 company comfort data bus in single wire-short to ground

I think that may be a break somewhere in the twisted can wires from memory?

[quattronutter]

Any likely suspects for a broken can wire? Its in single wire operation so it must have a break or fault somewhere,have checked drivers door loom and boot wiring,logging so many connection errors on vcds its tricky to know where to start

[quattronutter]

Still battling this fault which has now mutated! Ignition is back permanently now but now when driving multiple things lose power randomly including pas,traction,dash cluster crashing parking brake and adaptive ights flagging faults etc etc... battery is new and alternator is putting out good charge...had most of the interior out changing sunroof and no signs of water ingress anywhere...

[quattronutter]

Looks like alt clutch pulley has gone causing random alternator output and voltage drops,tricky one to spot

[quattronutter]

Still battling this fault,new alternator,vcds shows visible voltage drops on graph causing pas loss, dash cluster crashing etc...

[MikkiJayne]

Loose connection somewhere? I recall a thread a while back about a main power cable connection in one of the footwells which can overheat and fail and cause problems.

[quattronutter]

Rear batt pos cable was getting quite warm but have changed that,i think the main power feeds down driver side through footwell?

[quattronutter]

Junction box in footwell has good voltage before and after...

[quattronutter]

Swapped multiple body comfort and power modules but still no nearer a fix...modules begin shutting down causing a ton of errors loss of pas etc...