Been there done that. There are multiple speed sensors on the car, but the one that drives the speedo is on the back of the tranny. The code tole the dealer to replace the sensor when the speedo got twitchy. WRONG. I ohmed out the sensor (its a solid state device), and when the problem persisted, I made them put it back. I eventually got some copies of the relevant pages from the manual so I knes the connector layout. I ran a new set of wires from the sensor to the board. so far the symptoms are gone.

If the speedo is flat dead, check the wires going into the instrument panel printed circuit board.

NOTE: I paid a mechanic to remove the dashboard cover as this requires removing the passenger airbag. NO WAY was I gonna risk getting blowed up. Blowed up real good over a broken wire.

good luck,

doug