V70 brake fluid level error....

[Dikiz]

Hello, need ideas/advice on what to check with the car....volvo v70 2.4D 2002.
The error is Urgent Service - brake fluid(originally is in Dutch so maybe translation is not very correct (REMVLOEIST. LAAG SERVICE SPOED), and red light of course on the instrument cluster
What I did: checked fluid level was okay, and replaced, another brake fluid tank with the used one) with a sensor, after both were checked with a multimeter and worked identically, like a simple switch), The measured voltage on fluid level wires shows 12 volts when the ignition is on, reattached the connector on abs ecu....no changes. Sometimes error turns off, and reappears randomly(maybe related to speed, vibration, and temperature ...but I still don't know....but more time is error on.AFAIK brake pads don't have sensors(or i am wrong)?
No ABS light, or traction control erron on the instrument cluster so abs ecu should be ok...
I read here that problem can be with CEM module (where is it located?),maybe is it possible open at and visualy inspect it and cold soldering problem is?
Also read that can be instrument cluster problem....Code DIM-0005 “Red general warning lamp” stored.,so very confusing.....
What to check, how to find where the problem is...

Thanks for the ideas or advice

[Dikiz]

problem solved, at least for now, as i said I had one idea...and looks like I was right.
The problem was in the instrument cluster, resoldered all ICs,but the main suspect was the cold joint at the 7ch darlington sink driver(there are 3 such ic`s) they control when the LED turn on or off(simplified)....so maybe will be useful for someone.