Hey im haveing the same problem, its really wierd, if i have all my accessories off then my speed will register, but if i turn on my lights or hit the brake, or turn on heaters, it drops to zero. then i get code 17, also, if your car reads under 2mph vtec wont engage, but when i reset the ecu, it goes away, and it works fine for a while, i did a swap also. ITS PISSING ME off as well, I hope we can find out what the problem is.....