P0115 : Coolant sensor circuit issue

Sorry again for posting a third message in a row, but I just recently found a small amount of oil in the water system...
It would explain a misfire...
I think the car is a bust.

jamesrabel wrote: ↑Tue Aug 02, 2022 11:50 am I just recently found a small amount of oil in the water system...
It would explain a misfire...
I think the car is a bust.

Do one of these head gasket tests (eBay) before going any further.

The test can save you a lot of wasted time.

A failed head gasket is not uncommon and is repairable by a home mechanic, so it may not be a total loss if the head gasket test comes back as a fail.

jamesrabel wrote: ↑Tue Aug 02, 2022 9:36 am I do have a can of brake fluid right here, maybe attempt a quick start.

DO NOT put brake fluid in anywhere other than the braking system.

You should not be trying to run a petrol engine on brake fluid.

If you want to test the fuel system as Ozvtr was telling you, use brake cleaner (eBay) as a choice because there is usually a can of this very useful stuff in the garage or workshop any way.

You can also use this Easy-start is designed for engine testing, diagnosis and cold starting assistance but there isn't usually any of this to hand as it all gets used up

Ive never seen a gasket testing kit before, how does that work?

Also sorry i realised i put brake fluid, not brake CLEANER, im french so translating in my head doesnt always work

jamesrabel wrote: ↑Tue Aug 02, 2022 2:01 pm Ive never seen a gasket testing kit before, how does that work?

You use this special kit of chemicals to take a sample of the engine coolant.

The chemicals can detect combustion gasses in the coolant and change colour.

There should never be any combustion gasses in the coolant and the usual way they do get there is through a failed head gasket.

jamesrabel wrote: ↑Tue Aug 02, 2022 9:36 am I do have a can of brake fluid right here, maybe attempt a quick start. Wont brake fluid damage the chamber or remove the oil though?

NO! NO! Not brake fluid! Brake cleaner!
Use brake cleaner If you have some on hand. It's a hydrocarbon like petrol and vaporizes at room temperature. Otherwise use starting fluid.
Starting fluid is based on ether and will work on both petrol and diesel engines.
Both of them vaporize into a mist and mix with the air quickly.
Petrol doesn't vaporize as easily and is hard to get all the way down into the cylinders. It tends to stay as a liquid and pool in spots instead of going into the cylinders.

Don't be surprised if this doesn't work. It just means you have no spark. But you need to start eliminating stuff. At the moment, as you said, you have nothing to go on and no proof of what is and is not working.

Thanks for your input.

It just so happens that my 2005 diag tool has a demo mode, which pretends to be connected to a car, most likelry for educational purposes. In any case, all information i thought i had from the ECU was entirely faulty (i think im a fool)

Now trying standard DL17 connecter with a s50 citroen chip that is supposed to work on this model, i get no communication with ECU. Now that would explain the non start issue. What can i do to check whats going wrong here?
Im afraid im used to older engines, i wouldnt know what to check with a voltmeter on an ecu..