I need to know how to manually retrieve dtc...

This info is from the tech manual.....because you have a 16-pin DTC connector, you have the OBD II system in your car. This is cut and pasted info from the tech manual:

Fig. 2: A Tech 1® , or equivalent scan tool must be used to retrieve codes from 1996–00 models with the 16-pin DLC connector



If you look on your doorjamb and read the sticker, it will tell you the year of your car...and if it was manufactured AFTER a certain month, then you have the 96 model...and from what you are saying, you have a 96 model because it has the 16-pin connector and not the 12-pin connector that the 95 and earlier had.

Reading Codes OBD-I SYSTEMS

I'am not sure if you can retrive the codes without a scanner on cars 95 and up, but if you can hears how to do it, get a paper clip unfold it so you have 2 strate ends , take 1 end plug it in the last port to the right and the other end in the port next to it and turn the key to the on position, chk. engine light will come on and start to blink, if not keep moving the last one you pluged in to the next one and so on until it does, than you simply count the blinks, for example 1 blink than a paus then 2 blinks right together that would be a 12. but remember unless you got a book to desifer the codes it just as easy to take it to auto zone or any auto parts store and have it scaned for free.