[Ricflairandy]

Hi all,



Looking for some advice before I let a garage throw expensive parts at this.

Car is a 2014 BMW X1 xDrive diesel (ex police car) on 219k miles. It has stop/start and (as far as I know) the battery is original.

• First symptom: multiple warning lights came on while driving to work (ABS, traction, 4x4, red brake, airbag). Car still drove normally.
• After work the same day, the battery was completely dead.
• Car was jump started and driven home.
• Took it to a garage — they diagnosed a faulty earth/ground cable and replaced it.

• Got the car back and it was fine for about half a day.
Then the problems returned:
• ABS/traction/4x4 warnings back on
• PDC now fails immediately when reverse is selected
• At one point while driving, all gauges (speedo, rev counter, fuel) dropped to zero but the engine continued running smoothly, then cluster came back

Garage is suggesting it happens when the abs kicks in so it’s possible ECU failure (~£1,000), but given:

• The battery went completely flat at the start
• The earth cable has already been replaced
• Engine never cut out
• No limp mode
• No misfires

I’m wondering whether this is more likely:

• Failing AGM battery
• Voltage instability / charging problem
• ABS/DSC module fault

Would you replace and register the battery first given age/mileage?

Thanks