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