GF picked up a 98 base Prelude 5-speed this weekend with 2 codes. 02 which is easily replaceable and speed sensor. I don't understand why there'd be a code for the speed sensor since the speedometer is functioning properly and VTEC still engages.

Any thoughts? Thanks!

ps, we only managed a bit over 25 mpg with highway driving. I expect better mileage after I replace the 02 sensor.