Odd Xantia tachometer

[andy5]

I'm idly looking at some photos of a Xantia diesel for sale, and intrigued by one of the dashboard

The airbag and foglights indications are on, so obviously the ignition is. The RPM shown is off the top of scale, at about where 7000 would be if it went that far, or where a clock hour hand would be at about 5.30.

Has anyone seen or heard of this, and what does it mean? Would the instrument start behaving properly once the engine was running (if it isn't), and whatever the spurious input is has the needle flown off the top of the scale or somehow fallen down past the pin at 0?

[CitroJim]

It's a very common problem Andy... It's caused by trying to start the engine with the battery in a low state of charge...

The needle needs to be mechanically nudged back to zero but normally it results in no lasting harm.

There's a few threads on here explaining the various methods of doing it...