Ecu Fault Code #42

[AE110]

Dear all,

I m from hk and i owned a 1997's Toyota Corolla with the 1500cc 5AFE engine

One day i found that the Engine light comes up, then i check the fault code is 21 & 42 which

21 - O2 sensor problem ( This is because i disable the O2 sensor ... i will replace it soon)

42 - Speed Sensor problem

My Speed meter, everything seems ok, what should i do for this code 42 ?

Thanks all

Wilson