Emission control system

Hi we have a 2008 Nuevo after being left for a month or so started up only to find the emission control light on.I look this up on u tube and found it to be a common problem after standing up for a while the answer was to turn the ignition on and off five times. This clears the fault. Also advised not to use cheap supermarket fuel as this has no additives. So next time we’ll use decent fuel Hope this helps some somebody.

Good to hear that it worked for you, but there is an element of luck here - sometimes it will work and sometimes it won't.

The "emissions light" is simply an indicator that there is, or has been, a fault somewhere in the engine management system - and there are lots of possible faults (i.e. lots of components that might go wrong, in various ways). The intention by the manufacturer is that when it lights up, you are meant to connect a diagnostic reader to the diagnostic port and it will give you more information about which component is faulty.

In some cases, the fault can be intermittent - e.g. an actuator will stick the first time you use it, and then will free up for a while. In that situation, clearing the fault code can help - the fault may not re-appear for some time, if ever.

But in other cases, the fault will be permanent - e.g. a wire breaks or a sensor goes open-circuit. In that case, clearing the fault code won't help - it will simply come back every time you turn on the ignition, because (obviously) clearing the code doesn't fix the underlying fault!

The one advantage of reading the codes before clearing them is that it can give you a bit of advance warning that a component is on the way out, which may be helpful if there are long lead times to get a replacement.

Here's an example of a list of possible fault codes for PSA vehicles, which was actually posted by an owner on MHF: http://www.pikit.co.uk/peugeotmt/psa%20eobd%20p%20codes.html

[And BTW, the advice on avoiding supermarket fuels is maybe a bit arbitrary too - all diesel fuels have additives.]

I find it incredible how many times I’ve seen comments about supermarket fuel being inferior to other brands when the fact is that it is a product that must be produced to a standard that is consistently checked and monitored.
There is much more risk buying from a seller with low sales as time is the enemy for fuel storage. All fuel no matter what brand or performance level will stagnate over time.
The most likely cause of the engine warning light is a sticking pressure sensor or actuator due to standing unused.