stalling golf 2008 2.0tdi bmn

hi this jamie (keiser501). bit stuck on diagnosing this one. occasional stall out or sometimes just a "hickup"....even at idle. like a relay dropping out momentarily. restarts straight away, ticks over ok, then a little hickup again. owner says its got worse over the last week or so.....been doing it a month or two.
only code is "005766 - control module malfunction P1686 -006 programming error - intermittant. any ideas. ta.

Hmmm... nothing on the Wiki for either code. Could you post your Autoscan from this Golf?

How about battery connections, ground points and ignition switch, or relays for terminal 15?

Also watch the G28 engine speed for issues.

I have seen a few controllers more recently......... due to voltage spike from weak battery..........get stuck with a self generated glitch G28 signal and be on the bench........

Interesting enough this will block a re-flash session in car or on bench as a pre-condition not met.
Even if no DTC present.