Citroen C4 not connecting to ecu

Have you checked your car battery voltage ? tried a jump start ?

Yes I did check the voltage and jumped it. I even charged the battery the whole night. But still nothing.

What was the voltage ? If battery dud wont hold a charge no matter how long charged and jump start may not work either

It's 12.8v. The battery is 2 months old. Do you perhaps know the wire that supplies power to the ecu

I would be double checking ALL fuse boxes / fuses again . Sorry dont have a wiring schematic for that vehicle

Citroen C4 mk1 (2004 – 2010) – fuse box diagram
Yesr of production: 2004, 2005, 2006, 2007, 2008, 2009, 2010

Fuse box under the dashboard
Citroen C4 mk1 - fuse box - under dashboard
Citroen C4 mk1 – fuse box – under dashboard
Number Ampere rating [A] Function
F1 15 Central locking
F2 30 Central locking, deadlocking
F3 5 Airbags and pretensioners
F4 10 Diagnostic socket, brake switch, photochromic rear view mirror, ESP, coolant level sensor, diesel fuel additive system, power steering Clutch pedal switch (ESP, cruise control and speed limiter)
F5 30 Electric front windows, heated exterior rear view mirrors
F6 30 Electric rear windows
F7 5 Interior lighting
F8 20 Audio system, NaviDrive, display, alarm, front 12V socket, trailer relay unit, driving school module
F9 30 Cigar lighter, rear 12V socket
F10 15 Tyre pressure sensor – Auto, STOPLAMP switch
F11 15 Ignition, diagnostic socket, particle filter
F12 15 Electric seat, lane wandering alert, parking assistance
F13 5 Rain sensor, sunlight sensor, (6 speed) Electronic Gearbox System, engine relay unit
F14 15 Air conditioning, instrument panel, tachometer, airbags and pretensioners, trailer relay unit, bluetooth telephone
F15 30 Central locking, deadlocking
F16 SHUNT
F17 40 Heated rear screen
Citroen C4 mk1 - fuse box - under dashboard
Citroen C4 mk1 – fuse box – under dashboard
Number Ampere rating [A] Function
F36 20 Hi Fi amplifier
F37 30 Front left hand electric seat
F39 20 Heated seats
Fuse box in engine compartment
Citroen C4 mk1 - fuse box - engine compartment
Citroen C4 mk1 – fuse box – engine compartment
Number Ampere rating [A] Functions
F1 20 ECU engine management, cooling fan
F2 15 Warning
F3 10 Windscreen and rear screen wash
F4 20 Headlamp washer
F5 15 Fuel pump
F6 10 Auto, Xenon lamps, directional headlamps, canister purge electrovalve (2.0 16V engine)
F7 10 ABS ECU/ESP ECU, power steering
F8 20 Starter
F9 10 Additional heating control unit (Diesel), engine coolant level switch
F10 30 Engine electrovalve, water-in-diesel-fuel sensor, ECU engine management, injectors, ignition coil, oxygen sensor, canister purge electrovalve (1.4 16V and 1.6 16V engines)
F11 40 Air blower, air conditioning
F12 30 Windscreen wiper
F13 40 Built-in Systems Interface