C4 picasso mk1 2007 multiple faults

[jarrmar129]

Hi,
Firstly to anyone who takes the time to read and reply and offer any form of help or advice to my issues, I really appreciate it, thank you.
Right,

C4 picasso mk 1 2007 1.6 hdi diesel semi auto flappy paddle 6 speed box no dpf.
multiple warning lights abs eps wont change above 3rd gear (can if you flip into neutral then back to auto when in 3rd it changes to 4th ) epb not working etc etc
started with roughly 31 fault codes changed the nsf abs sensor and the wheel bearing as originally it showed as a fault this appears to have been fixed but I am still getting faults every time i scan
I have removed and cleaned the egr valve when i removed it it was stuck in the upper position cleaned it tested motor resistance all good.
when i tried to run actuator test on egr it wouldnt operate do i need to reprogram egr after cleaning
EPB works on live tests but wont stay on motors all working ok
I have attached my last scan please let me know what to try next.

this is my line of thinking somehow 12v isnt getting to whatever connecters or modules it should do am i correct ?? if so can someone show me what voltages i should be getting on what connectors please,

nearly forgot battery fuse boards connectors earths all been cleaned engine bay fuse board out atm being cleaned, brake pedal switches showing working on live data using topdon artdiag bt 800
at my wits end so any help be great

Citroen-C4-PICASSO_Pre-Scan_System-Report_2026-07-03_19-39-01.pdf

topdon scan report

(321.23 KiB) Downloaded 9 times

hopefully attachment works

[jarrmar129]

Forgot to add these

VIN NUMBER IS
VF7**************[VIN obfuscated, can be read by forum staff]
DOOR PILLAR STICKER BOTTOM NUMBERS ARE
11133FV
21159
KNYC

[mickthemaverick]

Having read through your report my inclination is that you have battery or earth problems throughout the car. Check the main earthing points to the chassis and engine/gearbox. I see you are already cleaning the fuseboxes so after refitting delete all the codes and run a new scan to see what remains.

[RichardW]

Start with the EGR valve, most of the other faults look like they might be coming from the ABS ECU spitting the dummy due to the engine ECU setting the EGR Fault.

You need to get on live data and see what position signal is doing. Is it jammed high at key on? Does it move with the request - the two should track closely. If you unplug the valve does the fault change?

[jarrmar129]

Mick never thought about earth's will check and clean possibly run a temp earth from engine to chassis
Richard, when I had the egr apart I tested resistance of the motor can't remember what pins and it all checked out OK from posts on here giving values I will run live data at weekend and see what happens.
Do you know what pins on say egr and abs ecu that I should test and what readings I should be getting I presume both units must receive a voltage at 12v and what pins for negative earth
Thanks guys

[RichardW]

It's not the motor it's the repeat signal that's causing problems. There should be 5 wires to the EGR valve? See this thread: viewtopic.php?t=65077 where there is a wiring diagram for a similar car (which may or may not be right! - but gives a hint). There should be 2 wires for the motor - I imagine this is a PWM 12V supply, but whether it is pulsing the +ve or -ve I don't know. Of the other 3, std for a 5v sensor - you should have 5V on one pin, earth on another, and the 3rd is the signal. It should go to 100% / 0% if you short it to 5v / earth (not sure which way round).

[jarrmar129]

richard thanks again i will post tomorrow evening once i have tested the pins on egr had a look at that post but the wiring diagram fried my brain i havent got the part designation codes each part is referring to.
now treading on dodgy ground here and i totallyrespect the forums views on this subject. but, if i install a certain plate with a hole drilled in the middle, am i correct in saying the mark 1 is the only model where said valve doesnt have to be mapped out on ecu. this purely a last resort if i need to buy a valve and just for test purposes only

[RichardW]

Item 1297 is the EGR valve, 3rd in from the right, bottom row. The connector is shown on the top. 5V NR to left of it shows that it is a 5 pin connector and is black (NR = Noir = Black in English). The numbers next to the wires show the number that will be printed on the wire somewhere (usually small) - PSA do not use wire colours. The numbers in the boxes on the connectors are the pin numbers - it's likely the position shown on the diagram does not correspond to the physical position! There should be pin numbers on both the valve and the connector, but they may be hard to see... The pin configuration is shown as:

1 - 5V reference for the position sensor (should be at 5v with key on) - wire number 1310
2 - earth for the motor I would expect this to show a good ground all the time - wire 1372
3 - motor power - I expect this to be a modulated signal for the motor, so difficult to read with a volt meter - wire 1371
4 - position sensor signal - this should vary from 0-5V depending on valve position - wire 1346
5 - sensor earth - should show good ground all the time - wire 1319

In this case blanking the EGR will do nothing as the ECU will still be seeing the wrong position and reporting the fault.

Edit: You can also see the other ends of the wires at the ECU - note whilst I pretty sure the EGR valve pin out will be OK (although wire numbers may differ) pin out at the ECU is less sure for different cars!

1 - Pin A4 on a 48 Pin Brown Connector
2 - Pin D2 on same 48 / Brown
3 - Pin C2 on 48 / Brown
4 - Pin D4 on 32 Pin Grey connector
5 - Pin D3 on 32 / Grey