KAD32 intermittent code 2.9
 

KAD32 intermittently throwing a code 2.9, engine backs off and throttle no longer engages until engine turned off and restarted. Can't find code 2.9 in any manual. Any pointers? Twin engines, only affecting starboard engine, dual throttle positions, happens at either position.
Happens at idle sometimes,, sometimes can cruise for hours without it happening, sometimes it can happen every few minutes. Hard to say, but seems to happen more often after running for a while and turning off engine for a short while, like at a lock, worst timing.

Edc?
 

Is it still a valid problem?