C4 Picasso - wheel related faults on dash

[danlat1415]

I've owned a C4 Picasso 2017 Flair model for a week, and today after not using it for a couple of days and it has been snowing, I am now getting faults on the dashboard that are wheel related - so I'm wondering if it's a sensor or wire issue;

- ABS braking system fault - repair needed
- ESP/ASR system fault - repair needed
- Hill Start system fault
- Parking brake fault - have vehicle repaired
- Tyre under-inflation detection system fault


The car had 2 wheels refurbished by the dealer before I bought it.
The car was driving fine for the first couple of days and now comes up with those faults.
I'm guessing either a wire/sensor issue, fuse and low battery?

The dealer I bought it from is over 300 miles away and I had to get it delivered, so I can't really take it back for them to check easily.

Can anyone give me any ideas what I could check for?

VIN is - VF7**************[VIN obfuscated, can be read by forum staff]

Thanks

[RichardW]

Most likely a wire to a rear ABS sensor is corroded / rubbed through. The recent wet / snow will have caused it to short out! Inspect the wiring carefully, but it might just be a very small greenspot, e.g.:

https://www.frenchcarforum.co.uk/forum/ ... 6&start=15

[GiveMeABreak]

If you bought it from a Citroen dealer with a Citroen approved vehicle extended Warranty, you don't have to go back to the same dealer - you can take it to any Citroen dealer under the warranty as it will be on their central database as covered.

In fact if you do have this warranty it is the best course of action as if you start fiddling about with it / undertaking work yourself, they may not actually cover it, so this being the case, let them deal with it. As long as there is a fault, any reasonable diagnostics will be covered (as per the warranty booklet).

[danlat1415]

Thanks for the replies.

Unfortunately, it was bought from a Toyota dealer who had taken the vehicle in as part exchange and it was for sale at almost trade price. Only has 6 months warranty with them, but they're definitely not local to me.

It doesn't have any Citroen warranty.

I was looking for pointers so I know where to check, as I assumed it would be a wire/sensor issue given the symptoms.

I'll check it out when I get chance at the weekend and hopefully it'll be a small wear that can be patched rather than replacing the ABS sensor.

When you say the right side rear - do you mean right side when sat inside the vehicle? Or when looking at it face on?

[RichardW]

It could be either side; that thread happened to be about RHS. Doesn't matter which side you pick to start on, bound to be the other one!!

[danlat1415]

Is it different to replace the rear ABS sensors?
Do you need to take the brake disc and hub off to access? Or can it be unscrewed from behind or through the brake disc hole? (Like in this video)


I'm just preparing myself. I'm planning on taking a look at the weekend, and if needs replacing rather than patching, whether it's something I can do myself.

[GiveMeABreak]

No it doesn't need the hub coming off. It's a matter of raising the car, removing the electrical connector, and undoing the securing bolt.

Just don't knock the new sensor as they are uber sensitive. When you've refitted the new sensor, tighten the bolt to 1 daNm.

[danlat1415]

Excellent, thanks.
That sounds like it's going to be less hassle just to fully replace rather than splice, solder and reconnect - potentially increasing resistance in the circuit and making it less effective.

Sorry to be a pain, and out of laziness as I've not yet looked at it, but it the retaining bolt behind the hub, on top or accessed by poking through the disc?

[GiveMeABreak]

Here you go:

Bolt at (1), sensor at (a)

[danlat1415]

Absolutely amazing.
Thanks very much.

I'll just order a new sensor and sort it all in one job.
Thanks for your help

[RichardW]

I've posted the part numbers, but it will be much easier (and cheaper) to repair the wire (if that is the fault). I can't say I've heard of anyone actually having to do a sensor - and I wouldn't buy one on spec before confirming the fault!

[danlat1415]

That was my thought too after finding out the sensor is separate to the wire on the rears.
I'll investigate first, then decide how to proceed.

Thanks again for your help.

[GiveMeABreak]

See my notes in the reply to your parts request post regarding the wiring Dan.

[danlat1415]

I've seen, thanks.
I was hoping the rears came with the wire attached, so I could just disconnect and replace rather than mess around with it
Bad luck for me.

I'll look at it sometime over the weekend.
I'll Diagbox it first to see if it gives and indication of the issue or side, then visually inspect and go from there.
I'm holding off ordering anything until I've checked it out.

[danlat1415]

I hadn't had much time to look into this as I only get the issue when it rains. The system works fine when the weather is dry.

I've ran a scan on Diagbox 9.129 (I though that may be best due to 2017 vehicle - I'd previously used 7.58 and 7.83 on my previous 2014 vehicle.)

Diagbox won't read the ABS ECU to give me any fault codes. It says ECU not recognised.
That's when it's raining and the issue is on - I may try again when it's dry and the faults go - as I'm now worried it's the ECU not the wiring.
Or hopefully, most likely, it's just the version of Diagbox I'm using.

Any recommendations on which Diagbox version would be best for my vehicle?

I've not taken the wheel of yet and examined the sensor or the wiring loom - I wanted to run diagnostics to give me an indication of which side to start with.