Is The C5 Really That Bad?

[Randombloke]

I've only noticed one oddity - once or twice a week, when starting the engine, it'll complain about brake fault, then ABS fault, and flash the stop light. Restart the engine, and all is well. There is no fault. This feels like a software glitch to me - maybe many of the C5's "faults" boil down to software bugs?

 

Hi Dan,

 

The C5 does not like a battery that is poor on either voltage or current capability. I would suggest you get a cheap voltage meter to plug into the permanent 12V outlet in the cabin.

 

Leave it plugged in then leave the car for 1 hour, say. Come back and get in, see the voltage drop as the hydraulic pump kicks in, then see how low it goes. If drops much below 11V check the battery in under the bonnet with a proper meter.

 

Check with your garage and let them test it if need be.

 

I would love some more input on this matter from kfk or iannez. Mine had a slightly low battery which recovered after a charge at the garage.

[Guest Dan Slatford]

Hi Dan,

 

The C5 does not like a battery that is poor on either voltage or current capability. I would suggest you get a cheap voltage meter to plug into the permanent 12V outlet in the cabin.

 

Good point, will try that soon. I can check the voltage easy enough. I expect there's nothing wrong with its current capacity, the starter starts the engine virtually instantly. Very impressive.

 

It'd be nice if the voltmeter in the dash actually was a voltmeter with some sort of calibration!

 

If I were to put the battery on charge, is there some procedure to go through before disconnecting or after reconnecting it? When even the interior light is under computer control, I somehow fear that pulling the plug will have "interesting" effects...

[paul.h]

Before disconnecting the battery I think you need to leave the car switched off for 15 minutes or more so the control systems can set themselves. I either read it in the handbook or on this forum. Not sure if any special procedure is needed when it is reconnected.

When the battery was a bit low on our C5 (had not been used for a month), it started as normal but then the 'Service' message lit up on the dash. It only cleared after running the car for a few miles and then restarting the engine.

On a separate occasion the brake fault light and Service message came on but not the ABS light. I checked the front brakes, found nothing wrong but moved the wear sensor wires in case they had an earth fault as though the pads were worn down. The warning cleared - I can not remember if this happened before the checks or during the checks since it was some time ago but it has not happened since.