I have a 206, I drive it home last Monday no problem, then following morning it wouldn't start. Battery OK, solendoid OK you can her it click on and off inside car, cam belt OK all fuses good. An engineer plugged his mini computer in and it did say sensor error but he couldn't tell me which one. He also undid a large diameter hose coming off the fuel head piece and sprayed inside it while I tried startingg it, nothing. Some sort of fuel to injector problem.
Anyone had same thing, any advice please, garages charge mega money to come out. Is there some sort of reset?
Please help

What's a a 206?

Does it crank when you turn the key? If not, the battery is an obvious culprit, though you say it's OK - how do you know? Otherwise could be the starter motor. If it cranks but doesn't catch then a prime suspect would be the fuel pump.

Buy an inexpensive code reader and check for codes. Everyone should own one, if they have a modern-day vehicle. At least borrow one and write down the code(s). Then, you can tell us what code was thrown. Just the same, I would remove and fully charge the battery and check all under hood and under dash fuses with a test light or multi-meter. Don't assume the battery and fuses are good--test them. Be sure to clean the battery terminals and connectors with abrasive cloth, plus check the battery cables for corrosion and hidden breaks.