Volvo Repair: transmission, flash flash flash, transmission control unit

Question
I have a 94 Volvo 850 Turbo, where the automatic transmission was having difficulty shifting to second gear when driving first thing in the morning, but after that it was fine.( the solution when it did that was to shift from drive to neutral and back.)  Now the overdrive arrow is blinking and the check engine light is on.  Any thoughts?

Answer
first I would check for codes in the transmission control unit.then check the engine control unit for codes.

here is how to check transmission codes.behind the passengers side head light are 2 small black boxes,1 marked A ,and 1 marked B.on box A there is a small wire insert the wire into the hole marked 1 on box A then turn the ignition key to position 2 but not started.then on the box marked A push the small button for 1 second then release it.the small red light will flash a code back as a 3 digit number.there is a short pause between flashes for a single digit and long pause between the different numbers.example:
a 121 would look like this flash.....flash..flash....flash
write down each code,then after the first code repeats its self then press the button for 5 seconds the light will light when pressing button then go out when released,then the light will light steady again when it does press button fo 5 seconds again,this should have reset the check engine light.let me know the codes. i will tell what they refer to.
         Rege

YOU CAN REPEAT THIS PROCESS WITH THE WIRE IN SOCKET 2 OF BOX a TO CHECK THE ENGINE CONTROL UNIT CODES.