High level diagnostic readout

Read this in Edmunds.com "T5-forum":

"Learned that there are over 15 separate ECUs (sort of like a vehicle LAN) that monitor the various functions of the controlled devices and that without even hooking up the big computer diagnostic system, there is a sequence that involves the ignition switch and the read button on the left stalk that can provide a high level diagnostic readout in the left-hand message window. I didn't get to see the exact sequence, but it is good info to learn for those (hopefully non-existent) future occasions where something is amiss and you're stranded awaiting Volvo roadside assistance."

Does anyone have more information on this?

Rale, Sweden

(V70N T5 2001, Silver, with (almost) all accessories, e.g. Television-set, nav. unit , telephone, radar, 4*50W amplifier, subwoofer (=10 speakers), Dolby pro logic system.....)

Aactually it is a very low level read out, all the modules/nodes are checked to see if codes are set, but it won't tell you what the codes are, so doing it won't get you anywhere that the check engine light being on, or the message that gets desplayed in the DIM (drivers information module) wouldn't do. You have to know what the code is by number and then know how to verify the failure, in order to repair what might be the problem.

WHAT YOUE ASKING ABOUT IS THE DIM READ OUT. ALL THAT WILL TELL YOU IS WHAT SYSTEM IS AFFECTED IT WILL NOT GIVE YOU ANY CODES.