QuestionQUESTION: I have a 2001 Hyundai Accent with 95,000 miles on it. My check engine light has been popping up when I start it so I checked the code. It said, "P 0722, output speed sensor circuit no signal." Which means nothing to me.
Is this something that would be covered under the Hyundai Powertrain warranty or an extended warranty, because I have both? Is it something small I can fix myself? And finally, would it be at all related to my car being low on oil despite a very recent oil change?
Thanks very much.
ANSWER: There's a known problem wherein the transmission control module (TCM) incorrectly interprets induced noise in the vehicle speed sensor (VSS) circuit as a VSS signal. Since the VSS and output speed sensor don't agree, the TCM believes there is a problem with the output speed sensor.
The fix for this is to have your TCM reprogrammed. Unfortunately, only a dealer will be able to do this for you, and the warranty on this servicing has expired.
If, after the repair, you continue to get code P0722, then replace your pulse generators (input and output speed sensors). You'd probably be able to do this yourself. It's simply a matter of unbolting and unplugging the old sensors from the transmission and installing new.
This issue is in no way related to your engine oil level.
---------- FOLLOW-UP ----------
QUESTION: Do I NEED to fix it? What if any damage am I doing to my car by not getting it fixed?
AnswerOne of the things that occurs when this code sets is that the TCM places the transmission into failsafe (3rd gear only). At cruising speeds, this will result in little more than a drop in fuel economy. But when starting from a stop, it puts tremendous load on the transmission, and over time can cause transmission damage. I'd recommend doing the reprogramming and then seeing what happens.
