Series of faults when starting 2017 C4 Picasso

[Mathemagic-1970]

So, this all started when sat waiting to fill up last week. When starting the car back up we started getting lots of fault alerts on the dashboard. Since this is a car where the battery is suspect (it had been sat for many months), I've just fitted a new battery and followed the excellent instructions elsewhere about resetting the BSI etc.

Anyway, at first I was just left with a single warning which seemed to clear OK. I then reversed it off the drive and started driving forward. I then had a series of warnings which, from memory, were the same as earlier in the week.

In order:
Engine fault: Repair needed
Tyre under-inflation detection system fault
Parking brake fault: Have the vehicle repaired
Hill start system fault
ESP/ASR system fault: Repair needed
ABS braking system fault: Repair needed

It feels like there must be one cause - why would all those systems suddenly fail at the same time?

The only think I haven't checked is the fuses in the fuse box - if anyone can point me in the direction of a fuse diagram, that would be great.

Any other suggested would be great - my car is already off the road for 3 weeks until that is repaired and I've borrowed this one, insuring and taxing it as a temporary car and now I have no transport.

Tony

[RichardW]

It's very likely to be a broken wire to one of the rear ABS sensors. If you have a diag tool it will tell you which one, but it's easy enough to strip the wires out the conduit and look for duff spots - it may be a small area. Was it damp when it came on?

[Mathemagic-1970]

The first time it happened, we had pulled up at a petrol station and were waiting with the engine off but the ignition on for air for a pump to become available. Sat for about 4 or 5 minutes before deciding to go elsewhere as the driver in front seemed to be doing their weekly shop inside. It was dry and hot. The series of alerts started when starting and setting off from the petrol station.

Tried a basic OBD-II device and the first code is U0415 invalid data received - antilock brake system (ABS) control module. I also have U1213(81) for control unit 3, U1213(81) control unit 4, u1213 power steering and C0031(62) left front wheel sensor.

[RichardW]

Seems it's the exception to the rule, and looks like you should start at the left front corner!

[Mathemagic-1970]

Car back from garage and, thankfully, just the near side front sensor and not any broken wires. One car out of two back on the road.