General: XC70 tacho not working amongst other things

[Kevin costello]

Good morning all, hopefully you help point me in the right direction. Have a 54 plate xc70 cross country but I guess it applies to the whole range, it’s a frustrating one. The problems are

Starts then then when restarts stops after about 30 seconds
When it does run tachometer drops to 0 after about a min
Battery and oil lights come on but proved that still charging and pressure
Cant retrieve codes as doesn’t recognise several readers
Various messages that come and go on the display

I have swapped out ecm’s with known good ones but will no difference, replaced key fob and pick up ring, replace dash DIM display and exact same results,

And help appreciated

[Simmy]

scan with vida with out doing this you will be spending a lot of cash on unnecessary parts vida will find your fault and suggest possible actions ask for help on here someone may have vida in your area.

[Georgeandkira]

Your symptoms are all over the place making Simmy's vida scan suggestion doubly worth it.

Until you get said scan you can:

Ensure your battery is fully charged. There are volumes which can be written on this topic alone, starting with the question, do you know how to test a battery or even what a volt meter should read at the top of the day. A near dead (useless) battery can spend 24 hours on a neighbor's borrowed old charger and be barely alive the next morning.

Couple that with bad charging system and you'll be chasing your tail.

Did you look around for frayed / damaged wires? Any soft, furry critters in your neck of the woods? (chewed wiring)

Any episodes / evidence of water incursion? (connection corrosion)

Any work recently done on the car? (inadvertent disconnections or forgotten reconnections)

Any "check engine light? (many cheaper readers don't "establish communications" with every car vehicle).

Best of luck.