I typed in '2 digit nissan obd1 trouble codes' to Google and got lots of
hits.

http://www.extreme-check-engine-light-codes.com/Nissan%20OBD1%20Decoder.htm
 is one.

14 means speed sensor.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos:  Non members can still view!
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A Chilton or Haynes book usually lists the ODB1 codes, because they are so
few in number compared to the numerous amount of OBDII codes. Most of these
can be found at auto parts stores such as Kragen or AutoZone.

From what I can tell from the "Haynes Repair Manual: Nissan Sentra & 200SX
1995 to 2004 All Models"... page 6-3 shows a Trouble Code chart - 1995
models, which shows code 14 as Vehicle Speed Sensor; page 6-5 shows a
Trouble Code chart 1996 through 1999 models, which shows code 0104 as
Vehicle Speed Sensor. This particular book also seems to have a
comprehensive list of OBDII codes for models 2000 and later.

(The ISBN of the Haynes Repair Manual I am referring to is ISBN 1 56392 576
1. There is also a smaller barcode with ISBN-13: 978-1-56392-576-4.)

http://www.troublecodes.net/Nissan/

On further thought, if your 1996 was sold as a 1996 model in the
USA it is supposed to be obd2 and not obd1 by Federal Law.
It should have an obd2 ecu and sensors and give four digit
powertrain codes.
Two digit codes are for 1995 and earlier.
In which case Code 14 = VSS.
Perhaps someone installed an older engine and ecu.