ABS no dialogue with lexia and multiple faults

hi guys I am a newbie so bear with me please.
I am have problems with my wife's car a 2006 petrol semi auto C3.
the fault came up suddenly :dashboard displayed anti braking system fault,air bag ,fog light,bright sensor,steering wheel hard and gearbox limited to second.
I managed to drive back home and plugged a cheap obd reader which came up with p500 wheel speed sensor.I thought thats easy just a speed sensor to change.
jacked the car checked sensors for resistance reading 1Mohm.At that time I did not know about passive and active sensors ,i ordered 2 and fitted them to the car and obviously there was no change as my speed sensors were active type and can t be resistance checked.
I have read all the posts in this website and to be honest it was very helpfull.as advised I bought a lexia diagbox and plugged it to the car .
diagnostic came up with multiple faults but the most important was ABS no dialogue with lexia
BSI not communicating with abs all the other minors faults.
all seems to point to the ABS module but my car is not worth that expenditure .I want to be 100% sure that the abs module is gone before scrapping the car which my wife does reall like.
the vehicule has only 40000 miles.
I disconnected the abs connector to check the wires and all seem ok no water or corrosion.
I checked them all with my tester and i got 3 wires 12v probably abs fuse F3 mf2 and mf3
the green was ground ok.
the other wires i couldnt check as i dont know which one is which.
the brake level switch is ok.
my question is which wires are the CAN bus network and could they be the cause of all these troubles or am I kidding myself and the ABS module is dead?
Does anyone has the wiring diagram for the abs and connector wiring colour codes.
thanks again for your suggestions.

Hi

You say many minor faults.

It would be interesting to know what they are.

Screen shots of lexia save a lot of typing, see the help section for info on screenshots and attaching images to posts on the forum.

Can you delete the codes (try to delete them all), some won't clear

Then drive the car to see which ones come back. Although it does sound like the ABS ECU is fried, it isn't very common. But you have lexia now and could change the abs unit for a second hand one to keep the car on the road.

Hi C3carguru
Thanks for this quick reply.I have Lexia now but I am just a beginner .it took me ages to get it to install and to work on my car .the worst is I selected English during install but it turned out in french??
The faults are almost all abs related:speed sensors,bsi/abs not talking,
I attach few photos .
If the AbS is dead it would cost me about £500 not too keen.
You wouldn't have the abs wiring diagram by any chance

Kim wrote: ↑Sun Dec 29, 2019 10:39 pm BSI not communicating with abs all the other minors faults.

Hello Kim

I wouldn't describe the screen-shots as minor faults.

You have ECUs not communicating and some 'U' codes which are the network faults.

Network faults would explain the high number of different serious faults you have listed.

If you get and can't clear the faults with ABS disconnected, you can be sure the ABS ECU is not affecting the CAN network.

I don't believe the ABS ECU is the cause of the errors, but a symptom of the CAN errors, do the test above to prove/disprove

The work on the U codes you have

U1108 and U1308

Kim wrote: ↑Sun Dec 29, 2019 10:39 pm You wouldn't have the abs wiring diagram by any chance

For this you would need Citroen SRDRE (here, eBay) DVDs.

Citroen-Driver wrote: ↑Mon Dec 30, 2019 2:08 pm

Kim wrote: ↑Sun Dec 29, 2019 10:39 pm BSI not communicating with abs all the other minors faults.

Hello Kim

I wouldn't describe the screen-shots as minor faults.

You have ECUs not communicating and some 'U' codes which are the network faults.

Network faults would explain the high number of different serious faults you have listed.

If you get and can't clear the faults with ABS disconnected, you can be sure the ABS ECU is not affecting the CAN network.

I don't believe the ABS ECU is the cause of the errors, but a symptom of the CAN errors, do the test above to prove/disprove

The work on the U codes you have

U1108 and U1308

thanks for your reply .you are right those are not minor faults I just thought that they would be the consequence of a faulty abs ecu.
From what you are saying if I understood well there might be nothing wrong with the ABS ECU but more with the CAN network?
I have disconnected the abs connector if this is what you mean and no change all the symptoms remain.can the car still operate without ABS connected?
I have cleared few faults but the comms faults wont clear,the gearbox not above 2,heavy steering etc.
where should I look to check the can network?
how come I can connect to all ECUs apart from ABS?I thought that abs has fried hence was not returning signal on can cable?
thank you again for your input.

Citroen-Driver wrote: ↑Mon Dec 30, 2019 2:12 pm

Kim wrote: ↑Sun Dec 29, 2019 10:39 pm You wouldn't have the abs wiring diagram by any chance

For this you would need Citroen SEDRE (here) DVDs.

thank you.

Kim wrote: ↑Mon Dec 30, 2019 5:25 pm From what you are saying if I understood well there might be nothing wrong with the ABS ECU but more with the CAN network?

Yes, this is my suggestion.

Kim wrote: ↑Mon Dec 30, 2019 5:25 pm I have disconnected the abs connector if this is what you mean and no change all the symptoms remain.

So this proves the faults are NOT caused by the ABS unit.

Kim wrote: ↑Mon Dec 30, 2019 5:25 pm can the car still operate without ABS connected?

No because you loose the power steering and automatic gearbox and ABS isn't working. Disconnecting it was to prove/disporve

Kim wrote: ↑Mon Dec 30, 2019 5:25 pm I have cleared few faults but the comms faults wont clear,the gearbox not above 2,heavy steering etc.

Well, either all the symptoms remain or they don't. Not sure what you mean here. You need to use lexia to scan for faults, clear the faults, scan for faults again and any that remain are permanent.
With the ABS disconnected, you will get steering, autogearbox and ABS faults.

Any faults not related to the ABS will indicate they are not due to the ABS, the U codes are bus faults and these are probably your problem.

Kim wrote: ↑Mon Dec 30, 2019 5:25 pm where should I look to check the can network?

You need to google the CAN BUS network to understand what it is. This is the point at which the car will become uneconomical to repair.

Kim wrote: ↑Mon Dec 30, 2019 5:25 pm how come I can connect to all ECUs apart from ABS?I thought that abs has fried hence was not returning signal on can cable?

There is some confusion on whether the faults cleared or not with the ABS disconnected. I would be looking to see that everything can be cleared apart from the ones that are connected to the ABS. Particularly the network U CAN bus codes. You can connect to ECUs but there is an avalanche of codes from them. You don't often see that many codes stored, even with a neglected car.

Getting Lexia back into English would help you and save all that google translate

Kim wrote: ↑Mon Dec 30, 2019 5:25 pm thank you again for your input.

You are welcome