transmission on 2004 Hyundai Accent

the check engine light went on; went to the auto parts store for a check engine diagnosis, was told that there was a speed sensor issue and multiple misfirings which could be the spark plugs or the cables. Replaced the spark plugs. now the car will not drive in reverse nor shift gears going forward. Does this mean I need a new transmission?

Asked by for the 2004 Hyundai Accent
Time out -
Please have a diagnosis performed by a professional. Not an auto parts store. They can't do it there. They can pull codes, but can't tell you what they mean for real and why they came up.

I can tell you that some Hyundais have OSS and ISS issues (that is output shaft and input shaft speed sensors). If the sensors are failed, it will pass faulty information to the processor about how fast the shafts are spinning. This will affect transmission operation.

Have a good diagnosis performed soon. Good luck.
1 more answer , 1 more comment
just from what i read, it sounds as if your wheel speed sensor issue may in fact be a vss. or vehicle speed sensor, as it is called will give you a code such as this. it also controls the shifting of the transmission. have this verified at your trusted repair facility to avoid just throwing a part at the car!
hope this helps!
if the speed sensor is repaired could that avoid having to replace the transmission?