Picasso 1.8 16v stops

Okay, to make sure the fuel pump is working, turn the key and crank the engine (even if it doesn't start). Then, press the fuel rail valve to see if fuel is spraying or if there's pressure. If not, run a positive wire directly from the battery's positive terminal to the pump's positive terminal, and then connect the pump's negative terminal to ground or the battery's negative terminal. Leave it connected like this and try starting the engine. If it starts, we'll have to look at the relay (which, by the way, I don't know where it is on this car, but we'll find it). For now, we're trying to figure out what the problem is, and this is one way to start troubleshooting. Best regards, and be patient, this needs to be fixed!

Here's a picture showing where the brown relay is located (in some cases it's black). It's supposedly not expensive (around €18-20), but first check what I mentioned earlier, including turning the ignition on and measuring with a multimeter if 12V is reaching the pump's connector.

The relay is the one on the right, behind the battery; it's circled in red. Cheers!

Hi mate, following your advice, I disconnected the fuel pump terminal under the tank and connected two wires, one to the positive (+) and one to the negative (-) terminal, as you suggested. The pump did indeed start, and fuel finally reached the fuel rail, but the car won't start. I checked the pressure with a gauge, and it reads 3.5/4 bar, which I think is sufficient. I believe the problem is electrical because when I turn the ignition on, the terminal I disconnected to connect directly to the battery from the pump isn't receiving any voltage. I think it should be
getting 12V, but it's only reading 0.2V, so whatever is supplying power to the pump isn't working, or it's not activating, I don't know.
But I'm guessing that if I connect the pump directly and fuel reaches the injectors, it should start. So now I'm stumped. If you could give me another step to take, I'd appreciate it, as I've been following your advice. I went to the service center and they told me that the fuel pump control unit is located inside the car, under the steering wheel. I checked all the fuses with a multimeter and they were all good. I saw a purple relay, tested it and it worked. I connected it to the battery and heard a clicking sound as it switched on and worked (I think it's for the heater or fan, I'm not sure). I also checked all the fuses in the engine compartment above the driver's side wheel well and they were all good, so I don't know what to do anymore and maybe the problem is more serious. Well, I hope you can give me some more guidance. Thanks for your advice.

Oh, and I can't see the photo you said you sent; I can't find it in your message. Just so you know, the battery in my Picasso is under the driver's seat. Is that where the relay is located?

Hi genis149, I see you've noticed there's no voltage reaching the pump. Logically, for an engine to start, there needs to be fuel and spark. So, if I'm not mistaken, they have a relay that powers the pump and the ignition, called an "injection relay" in Citroën or PSA vehicles, a "bitron" or something like that, in others a "tachometer," etc. In your case, you should check if you get a spark at the spark plugs when you turn the key and crank the engine. This needs to be checked too, because if you connect the pump directly and there's pressure in the fuel rail, the injectors also need to open or "pulse" (I don't know if you checked this too), and of course, there needs to be a spark for it to start.
I can't seem to send the photo (I don't know if it's my computer or the website?). Search online for: "Picasso gasoline injection relay." Well, apart from what I've already mentioned, the crankshaft position sensor is very important, but it's not shown in the diagnostic report you provided, so we won't check it for now. Check the previous items: the injector pulse (using a test light, for example) and the spark at the spark plugs. Cheers!

I forgot to ask you what type of engine it has and the year, to see if I can help you find where this relay is located. From what I'm seeing, it's usually near the battery, but it depends on the model. Another thing to consider, if the relay is working, is the key coding; try starting it with the other key (this is less likely to happen, but still possible). Well, let's see if we can figure it out! Cheers!