Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

This is the place for all your Diagnostic related questions or advice.
MMSGARAGE
Posts: 3
Joined: 09 Oct 2025, 00:21

Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by MMSGARAGE »

Hello
I'm a mechanic and I have a workshop in Portugal.
I really need someone's help.

I've been working on a van for 2 months and I can't solve the problem!

Citroen C4 Gran Picasso B78 1.6 HDi 2013
VIN: VF7**************[VIN obfuscated, can be read by forum staff]

I arrived at the workshop with the ABS light on and the electric parking brake not working!

I ran diagnostics with DiagBox, and the ABS/ESP/PARK BRAKE module isn't communicating.

I tested the wiring and it's ok.
I tested the CAN lines and it's ok.
I tested the fuses and it's ok.
I replaced the ABS module, but it's still the same.
I tested it with another BSI from another car, and it's not communicating.

If anyone can help me, I'd be very grateful! I'm desperate.

Best regards!
Top
User avatar
Huskyxantia
(Donor 2025)
Posts: 3392
Joined: 30 Jul 2018, 22:11
x 743

Re: Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by Huskyxantia »

Have you changed the reluctor rings ? If it has any
Husky. :? Thinking outside of the box is better than sitting in a dark one.
:-D
Top
User avatar
Huskyxantia
(Donor 2025)
Posts: 3392
Joined: 30 Jul 2018, 22:11
x 743

Re: Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by Huskyxantia »

Also anything on this circuit that has a plug checked them ? Corrosion on the pins can cause this, is it your car , was was it like before this fault happened ? Double check all the looms , wiggle them aswell , get ohms reading to all the abs sensors as sometimes poor signals can be causes of this fault, hope this might help
Husky. :? Thinking outside of the box is better than sitting in a dark one.
:-D
Top
User avatar
Huskyxantia
(Donor 2025)
Posts: 3392
Joined: 30 Jul 2018, 22:11
x 743

Re: Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by Huskyxantia »

Also the brake switch can be faulty can cause this issue too
Husky. :? Thinking outside of the box is better than sitting in a dark one.
:-D
Top
MMSGARAGE
Posts: 3
Joined: 09 Oct 2025, 00:21

Re: Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by MMSGARAGE »

Good morning! I didn't replace any of the phonic wheels. The car isn't mine, it belongs to a customer. It was like this instantly. I checked all the connectors, no corrosion. I'm going to check the brake switch, but if it were that part, wouldn't it malfunction? I can't access diagnostics with the ABS module.
Top
User avatar
Huskyxantia
(Donor 2025)
Posts: 3392
Joined: 30 Jul 2018, 22:11
x 743

Re: Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by Huskyxantia »

ive heard and seen myself with a car i once owned my reverse lights didn't work nor the brake lights , I swapped the switch for a new one my problem was solved
Husky. :? Thinking outside of the box is better than sitting in a dark one.
:-D
Top
User avatar
Huskyxantia
(Donor 2025)
Posts: 3392
Joined: 30 Jul 2018, 22:11
x 743

Re: Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by Huskyxantia »

It's like these lives all seem to be near the same area and when one thing goes it messes other things up too.
Husky. :? Thinking outside of the box is better than sitting in a dark one.
:-D
Top
MMSGARAGE
Posts: 3
Joined: 09 Oct 2025, 00:21

Re: Citroen c4 Picasso 2 b78 ABS Not comunication PLEASE HELP

Unread post by MMSGARAGE »

Solved...
New abs module fault, replace for new one and repair wire brake rear eletectric and every thing is right.
Thanks
Top

Return to “Diagnostics”