The 16 flashes just mean there is a problem, you have to put it in to diagnostics mode to get the error code flashes.
The sequence is in the R34 service manual, if you can't find it shoot me a PM and I'll dig it out when I get home.
I had an issue where I unplugged the ECU (TCM is in the ECU) without disconnecting the battery (my bad), all of a sudden I was getting A/T errors, first it said Shift Solenoid B and Lockup Solenoid, I was like WTF! Disconnected battery, drained power, unplugged/replugged ECU then it tried to tell me the TCM was fubar'd, reset it again and was all good.
I would suggest making sure the -ve battery clamp is on nice and tight, ages ago I was getting random dropouts as far as power and A/T went, engine would cut out briefly or transmission go in to limp mode, turns out the -ve clamp was a bit loose and was causing things to lose power over some bumps or heavy braking.