You're right to understand that parts might not be required. When a sensor is referenced in a diagnostic fault code, it is the cause of that code only about half of the time.
The first thing is to unplug the sensor and inspect the terminals, especially when the problem is intermittent. Look for the obvious corrosion, but also look for stretched terminals that aren't making good contact. They can usually be tweaked with a small pick to make them fit tighter.
There's different designs of speed sensors. Yours has three wires which means there's electronic circuitry inside it. That is often intermittent and is going to cause a lot more failures than the simpler two-wire sensors that just generate a voltage pulse from a spinning internal magnet. I can't tell from the pictures if yours has a gear that snaps onto the sensor or if it detects the teeth on something spinning inside the transmission. If there is no gear, there will be a magnet on the end and that can collect metal filings that interfere with signal generation. Those filings will feel like a thin black mud. Clean that off and try it.
We never like to throw random parts at a problem, but in this case the cost of a speed sensor is low compared to what you'll pay for diagnostic time. If the new sensor doesn't solve the problem, you've ruled out one of the easier suspects and you can save it for next time.
Saturday, October 18th, 2014 AT 1:14 AM