2004 xc70 with intermittent cruise control and radio issues on ignition

[enotslim]

Cruise control doesn't function and the radio controls on the steering wheel don't function. Sometimes. But sometimes they do. And the functional state of each is determined at ignition. When starting the car, cruise control may or may not work. And it stays that way until the engine is turned off and restarted, at which point it again may or may not work. Same for the radio controls. Controls on the radio itself always work fine. And the cruise control and radio steering wheel controls aren't always affected at the same time. I haven't noticed any other patterns of failure, but they may be there. Seems like these symptoms may point to a specific dysfunctional part or parts. I have not found this behavior described online, but it may there also.

Any suggestions would be great. Intermittent problems are difficult to troubleshoot.

Thanks,

Dave

[abscate]

Maybe catch me in Boston sometime and read DIM codes? I'll bet some are set

[enotslim]

Having lots of fun with my Autel. Had many codes = set 1 below. Cleared them. Drove about ten minutes up tp 50 mph. Cruise control and radio buttons did not work. Then many fewer codes = set 2 below.

I know completing a "drive cycle" (or maybe two) is important to ensure that all ODB-II tests are valid. Is the same true for non-ODBC DTC like these? I know it is for at least some because I have watched them pop up with driving. Will most of the codes in set 1 likely recur with more driving? I expect the two intermittent codes will become permanent.

Set 1:
ECM-928C

CEM-821C
CEM-6A03

REM-8F10 signal too high permanent

SWM-000A faulty signal permanent
SWM-0028
SWM-002A
SWM-002B
SWM-0009 signal too high permanent
SWM-0008
SWM-0029

DDM-002B
DDM-0024
PDM-002B

Set2:
ECM-928C faulty signal

REM-8F10 signal too high permanent

SWM-000A faulty signal intermittent
SWM-0009 signal too high intermittent