Early C5 V6 issues with "STOP" light and main screen

[raggerminder]

I recently bought a C5 Exclusive (Y Reg) with some issues. The car has only done 62k miles.

The main areas of concern are the red stoplight illuminating every trip after a couple of hundred metres and the main screen on top of the dash not functioning at all. Ignoring the instruction to stop doesn't seem to be as reckless as it would be in a BX or XM as the car drives very well: steering, brakes, suspension, performance and autobox all function normally.

Chris Andrews has very kindly put it on to a Leaxia for me and it has thrown up a range of faults, some of which have cleared and others remain. Below are the relevant screen shots (hopefully). Our first thoughts are that the problems could lie with temperature and engine speed sensors. I have no clue about the screen electronics. All help, ideas and suggestions will be appreciated.

[GiveMeABreak]

The first thing I noticed is that you are showing a low battery voltage 7.4 to 11.6 volts on several of those screens.

Other faults aside, I would get your battery checked out - how old is it and when was it last replaced. A poor battery will cause multiple electronic faults. In order to rule that out you really need to be confident in the battery health before going further.

Obviously there are some faults commensurate with age like the catalytic converter, but many other faults may be symptomatic of a bad battery.

[raggerminder]

Will try the new battery first, it's on order.
Is there any mumbo jumbo to be followed on these as there seems to be when changing batteries on some more modern cars?

Regards

Rob

[GiveMeABreak]

It’s all here:

viewtopic.php?f=51&t=61997

[raggerminder]

Thanks for that. What a palaver!!