The speed sensor on a Honda Accord, like other sensors, is electronic. You cannot "see" a problem with the sensor. It might give off clues, such as stuttering or, more commonly, having a dead spot at a certain speed, but you must use a scanner to tell if it is bad. Some mechanics have a computer that hooks up to the OBD diagnostic link connector, such as Snap-On's Vantage or Matco's 4000. Some of the computers only give parameters, which means you must know the specifications of the speed sensor in order to properly diagnose it without a code scanner.
Hook the code scanner to the OBD diagnostic link connector under the dash and just to the left of the steering column.
Press the "Read" button. The scanner will read the codes given by the computer. The code for the speed sensor on the 1998 Honda Accord is P0500. If the code comes across the scanner, the problem is with the sensor. If another code appears on the scanner, repair the other problem first then start the vehicle to see if the speed sensor code appears. If not, there is no problem with the speed sensor.
Replace the speed sensor. Plug the scanner into the OBD diagnostic link connector. Press the "Erase" button to erase the code. Start the engine. If the check engine light does not come back on, test-drive the Accord. If the light comes on, repair any problems with additional sensors.
