Abs fault code 121
 

Can anyone tell me what could cause abs fault code 121 on a 1995 t5r with obd1

Left hand front wheel sensor...

May be just dirty, loose/dirty connection or faulty sensor.
Or may be caused by cracked or damaged reluctor ring.

Could an intermitant open circuit in the wiring cause this code

Yes, that would be one thing to eliminate first.

I would look very hard at the reluctor ring - lots of these are going, but they are easy to fix with a new ring - very difficult to diagnose without a means of looking at the raw signal out of the sensor (oscilloscope) because the rings can crack internally.....