Citroen c3 1.4hdi won't start

[Trev2007c3]

Hi guys, I'm sure somebody has had this issue already... Or can at least point me in the right direction.

My c3 2007 1.4hdi desire won't start. I get a Single solenoid click from the bsm when the key is turned.
So far the car has had:
New battery
New starter motor
Replacement bsm
Replacement bsi
ECU immobiliser unlocked

Starter turns engine when solenoid is jumped from battery.
Checked all earth cables.
All plugs look clean and corrosion free.

Still getting the same error codes as before parts have been replaced
Error codes: on a topdon
Bsi:
0015 no Comms with engine ECU
Abs:
U1308 no Comms with engine ECU no signal
U1108 no Comms with engine ECU no signal
Power steering ECU:
U1108 engine ecu reception faulty.

All of these are permanent faults.
After replacing all the units above I'm at the point of checking individual wires, does anybody have a clue where I need to start with this process?

Vin number is: VF7**************[VIN obfuscated, can be read by forum staff]

[RichardW]

Can you actually access the engine ECU with the scan tool?

[ozvtr]

My c3 2007 1.4hdi desire won't start. I get a Single solenoid click from the bsm when the key is turned.
So far the car has had:
New battery
New starter motor
Replacement bsm
Replacement bsi
ECU immobiliser unlocked

The starter in the facelift C3's is run from the BSM BUT the BSM will not engage the starter until the engine ECU is happy that everything is kosher. If the engine ECU is not communicating then the starter wont engage.

You didn't say what engine ECU you are running so I cant tell you where the power goes to on the engine ECU. I cant decode VINs. I cant see the VIN anyway.
Stand-by power comes from the BSI, pin 10 of the 40 pin black connector. Main power comes from the BSM pin 5 of the 28 pin black connector.
Stand-by power should be available if the car has "woken up". So with the key set to ignition, there should be power on this line.
The engine ECU controls the engine ECU main power relay in the BSM. I don't know when the engine ECU latches this relay. With the ignition on? Or, like the starter, only when the ECU is happy? I don't know.
However, the engine ECU should be able to communicate if it has stand-by power only.

The other thing is that the CAN BUS for the engine ECU goes through the ABS module. The electrical connector on the ABS module is known to corrode from salty water. Despite the connector being in a plastic bag and having grease on the contacts, water can get in. The ABS module is under the near side headlight.