O/D (Hold) light flashing help
 

Hi All
I have an automatic 1998 Mazda Familia (Protege) that I am having trouble diagnosing a transmission issue. While driving the 1st gear change is ok, but the second wont change. The engine will rev and the hold (O/D) light will start flashing.
I believe it has an obd1 diagnostic port and I have used an LED to get codes - the paperclip connects GND and TEN while the LED connects FEN and B+ (see picture). Is this not reading engine codes and not transmission? I don't appear to have the TAT and FAT pins that I thought would be used for the trans codes.
The 2 codes I do get are 27 (2 long, 7 short flashes) and then 13 (1 long, 3 short flashes).
I was expecting a shift solenoid code.
Any help would be much appreciated!
https://cimg7.ibsrv.net/gimg/www.maz...17bfe685ea.jpg