DIM/speedo failure
 

Whilst driving a couple of weeks ago the entire speedo assembly switched off but the car still drove

A couple of days later the dash re energised and all was working except for the fuel gauge (reads zero/empty) also an Anti skid and SRS fault


I sent the DIM off for repair as I thought that was the issue but they have stated the XC90 has a later LED dash, even on my 53 plate example, that isn't repairable and it may be a CEM fault

Any ideas?

Forgot to say when the DIM went blank the windows and sunroof stopped working also

Look for the common factors: power feed to the DIM, sunroof and windows
Or the CAN bus

Power feed comes from CEM, so remove CEM and inspect for water damage

A small amount of corrosion in the CEM, looks to have been coated with a protective film from the factory

More pressing is I've found the carpet at the bottom is wet, I suppose a connector could be corroded

Get the CEM professionally repaired, you may be able to save it. Inspect connectors for damage.


And make sure you fix the water leak: either sunroof drain and/or the wiring loom entry point under the scuttle panel below windscreen.

The CEM may well be fine, water getting into vehicle CANbus/comms connectors will cause the issues you have. My V60 had a variety of 'interesting' issues like yours (occasionally dead dash and infotainment displays, multiple warnings and alarms, loss of electric windows and central locking, etc) because of a leaking rear washer pipe dripping onto under-dash connectors. A pipe repair followed by a careful drying of the affected connectors (plus an application of switch grease to the connector pins) brought about a full repair with apparently no permanent harm caused.

I just looked at the photos again

That's quite bad corrosion, it needs to be professionally cleaned and fixed immediately

You need to clean the circuit board with isoproyl alcohol, at best in a bath
Then the solder joints and tracks need to be inspected and repaired as necessary
Afterwards, the conformal coating needs to be reapplied for continued protection.

You also need to clean all corroded metal work.

And you need to clean all connector pins in the connectors that connector to the board

And then fix the water leak...