Crank no start citroen c2

[Danckobanko]

Hi,
my fathers citroen c2 1.4 kfv 2005 recently had a BSM that shorted out causing it to melt itself and damage some parts of the wires and connectors.
After fitting new cables connectors and BSM the car has a crank no start. I am wondering could it have damaged the ECU or the BSI too? I took apart the BSI and it does not look burned anywhere.
The ECU has no DTCs.
Any help would be apriciated.

[ozvtr]

WOW! That BSM is toast! Any idea what happened? My guess is the battery connection at the BSM was loose and generated enough heat to set the PCB's on fire.

Ok, so it looks like a MK1 BSM. Can you poll the engine ECU? My guess is no power or incomplete power to the engine ECU. The BSM is only controlling power to the engine ECU. The engine ECU grounds are external to the BSM.
There are 2 power supplies to the engine ECU from the BSM.
One is from fuse F4, this goes out pin 12 of the 16 pin green (vert) connector of the BSM.
Fuse F4 gets its power from the ignition key switch through pin9 of the grey (gris) connector.
Another is fuse F8, out through pin 8 of the 16 pin black (noir) connector Of the BSM.
There is a "power latch" ground from the engine ECU to pin 13 of the 16 pin black connector. This supplies a ground to the relay that supplies power from pin 8 of the black connector.

There is another power circuit for the O2 sensor heater circuit but that's irrelevant.

[Danckobanko]

hey, thanks for taking the time.
I have already checked fuses 1,2,4,8,15 they are all ok.
I will check for those grounds and powers tomorrow.
Right now I'm wondering if your car primes the fuel pump on ignition or not. I can't hear it turn on with the ignition. The fuel pump fuse gets a + only when cranking.
Also, does the ECU have a ground through its case or does it have it on a connector.

[ozvtr]

Right now I'm wondering if your car primes the fuel pump on ignition or not. I can't hear it turn on with the ignition. The fuel pump fuse gets a + only when cranking.

As a safety device, the engine ECU controls the fuel pump through the BSM. The engine ECU will only do the following if the correct key is used. When the key is first turned to ignition the engine ECU runs the pump for about a second and stops. When the engine begins to rotate, either with the starter or running, the engine ECU will run the fuel pump. If the engine stops rotating but the ignition is on (stalled or crashed) the engine ECU will stop the fuel pump. Of course it stops the pump when the key is turned to off.
Hmmm. If the fuel pump runs and stops then the engine ECU is not completely dead ( I mean without power). Check powers at the 16 pin "black" connector of the BSM. Pins 9, and 16. These supply power to the injectors and coil pack. Engine wont run without one of those.

Also, does the ECU have a ground through its case or does it have it on a connector.

The case is most likely grounded for shielding against radio frequency noise, but the case is not grounded per se. Not in the C2 anyway. It sits completely in the plastic battery box, isolated from ground. 'GROUND' is provided to 4 pins of the engine ECU.
Pin H4 of the 32 pin "black" connector. H1 of the 32 pin "grey" connector. Pins H4 and M4 of the "rust" coloured connector.