07 2.7HDI Display issues - AdrianLo
G'Day People...
I've had a C6 from new (now 18 months old). From 3 months of age it's developed an intermittent display fault... all displays turning off completely for indeterminate periods of time, or HUD glowing bright blue and then scrolling off the side of the screen. It has also switched off the ignition whilst in the fast lane of the motorway, resulting in no power to any systems. Has anyone else had a similar issue as my dealer is at a loose end?
07 2.7HDI Display issues - gordonbennet
You sound remarkably cool about this Adrian, the display wouldn't worry me unduly, however the cutting out at cruising speed would have had me jumping up and down by now, and i would have been demanding a replacement vehicle until the car was repaired 100% or replaced permanently.

I have heard down the grapevine that some C6's have had minor wiring loom work/replacements, but dashed if i can remember what the problems were.

Has your dealer called in Citroen engineers to help diagnose this problem?
07 2.7HDI Display issues - Screwloose

If it's anything like a 607; I'd start with changing the underbonnet fuse box.