Volvo Repair: 1994 Volvo 850SLE Automatic, engine oil dipstick, transmission control unit

Question
Dear Sir(s)

Background:
I purchased my Volvo 850 SLE (non turbo) new in Japan (where the car and I remain), in 1994. I have always had the vehicle serviced as per instructions in the owner's literature, and have never needed to have any other repairs carried out on the vehicle. The car has now travelled approx. 160,000km, on combinations of a 30 minute commute to and from work each day, and frequent longer journeys around various parts of Japan on weekends and holidays.

Problem:
The car has very recently developed the following symptom: Apprximately half of the time when I go to drive the car to work in the morning, the upward pointing (yellow), arrow on the lower, right hand side of the dashboard display 'flashes', while the engine revs increase as I push the accellerator pedal, but the car only moves very very slowly forward (when D is selected).

The first time the symptom occurred, I immediately checked the transmission fluid level (with the engine idling as per the owner's literature), which was clean and up to the full mark on the yellow transmission fluid (not the red engine oil), dipstick.

At this stage, I would be very grateful for any advice you may be able to give regarding what you suspect the most likely problem(s) may be, and even instructions on how to go about remedying the problem(s).

If you think the problem is not terminal, as I am reasonably mechanically capable and have a small workshop, I wouldn't hesitate to carry out the repair work myself; unless you especially recommended otherwise (for example if removal of the transmission is required, or possession of specialised / expensive tools is neccessary). In any case, I would appreciate it if you would be willing to provide some explanation about steps that will need to be taken in remedying the problem, so that I may then explain this to the people at my local workshop.

Sincerely

Dale Rizzuto

Answer
first I would check for codes in the transmission control unit.below is how to do so.most common problem is a bad gear position switch which is on top of the trans. where the shift cable attaches.it does require a special tool to install it.

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 then turn the ignition key to position 2 but not started.then on the box narked 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