l have a peugeot 405 est diesel unfotunatly dont have a hand book and a warning light has started to appear on dash ( -u-) kinda looks like the symbol in brackets can any one help me please

It might be the ''Brake Pad'' thickness wearing down light. That is more like (O).

It could also be the ''low brake fluid symbol.'' Which has an exclamation point in the middle?(O!) ! inside the O.

Does it look more like a spring inside parenthesis? (∂∂) This could be the glowplug warm-up lamp, but this comes on for a short time BEFORE u start the car, every time? Have u noticed that before?

Honestly madame, l have the SAME CAR, & l can not know from ur (-u-) symbol. l am fooled by the ''u''.

Please look under the bonnet & check the brake fluid level, in the white plastic reservoir. As ur brake pads get thinner, over time, they squeeze closer together. A little metal pin comes in contact with the metal brake caliper. Electricity flows through the pin & lights up ur warning lamp.
This ''thiness'' of the brake pads also makes ur brake fluid level go DOWN. So the two r related.
Have someone remove One front wheel, or put the car on a lift, & check the brake pad thickness.
Good luck.

Looks most like the preheat light, but l would think that you would know that one as it comes on before starting the engine for a few seconds. No other ideas on this one. if it is the preheat light then there is a problem with the dashboard wiring.

The only symbol in my handbook that looks like that is water in the diesel filter. it looks kind of like a cooking pot with a lid? it says to contact a Peugeot dealer asap! hope this helps.

NEIL B is correct.
you have an xud9/9td engine & there is a switch on the filter housing
sometimes they go faulty so try this
under the bonnet u will find the fuel filter housing to the right of the inletr manifold
behind the housing u will see a plug going into the housing unplug it & see if the light goes out
if so u have to try to remove water from the housing using the drain valve at the frontopen it & wait till it stops pouring close it & use the primer pump to fill it again
start the car & if the light is still on replace the switch

If you email me l will email you the part of the hand book you require . steve.atkins4.co.uk