i have got 2 spare speedo sensors for the ka24 ti manual, before i found out it was the cog set up that spins the pulse sender. would be wise to check that as well. The sensor screws to it, undo the sensor and one 6mm bolt and it will pull out. The plastic cog on mine was shaped like a U. But all good now.
If your car starts stoping at 2,500 rpm for limp home that will be the reason.