C3 picasso F40A code

[Ddclutch]

I am getting an F40A code on my C3 Picasso. It has come up several times now and doesn't appear to being triggered by anything obvious or any driving conditions. It might go for 2 miles, or 100, before the management light comes up. It then remains ( doesn't self cancel) until I erase the code. On the diagnostics it appears with the text "Oil gauge - Not characterised" which I dont understand. What does this mean? It isn't low on oil - the on screen check oil isn't coming on and oil is correct on the dipstick.
Bad sensor connection perhaps?

[GiveMeABreak]

Don't worry about it, but just check the oil level using the dipstick.

The fault is triggered when the system takes an Oil level measurement when the engine coolant temperature is higher than 40°C.

The oil level is measured up to a certain engine coolant temperature. Fault code F40A is recorded, if the oil level has not been measured, as the temperature of the engine coolant was higher than the set threshold. Fault code F40A will be cleared from the list of faults in the built-in systems interface when the oil level is measured.

[Ddclutch]

Thanks Mark, quick and helpful reply, as always from you.
Certainly easier checking oil on dipstick than getting out the code reader and running diagnostics!

But does this then also suggest a cooling system problem?

[Ddclutch]

Further to this F40A code. Checking the oil level with the dipstick doesnt clear the code but I can erase it with my code reader. But it keeps coming back, so something must be triggering it. It seems to happen when edging forward in heavy traffic, though with winter conditions and fairly soon after setting off from cold the engine doesn't seem hot, and certainly not overheating.
It may not be critical, but its annoying me! Is there anything I can do to isolate what might be causing this?

[GiveMeABreak]

Just ignore it. It's an internal BSI code and will not clear if the conditions when it takes an oil check are present.

[Ddclutch]

I would ignore it if it were just recording the code. But the engine management light is on continuously, which means that should a real problem arise this would mask the alert. It also posts an on screen error box every time I set off, saying "engine fault, service needed" and giving a loud beep. Its just annoying me.

It used not to do this at all so something has changed. Either a real life condition or a faulty sensor of some sort.

[GiveMeABreak]

Oh, OK, I wasn't picking that up from your post, so if you are still getting warnings, then either something else is wrong or the oil sensor may need replacing.

[civvie]

You can be sure the MOT tester will pick it up and ruin your day.