1997 maxima PO500 VSS Help

[pjq45]

Hello I am trying to help a friend out. the check engine light is on. The codes came up as PO500, PO325. So I put in a new VSS for code PO500 and the code is still coming up in the computer. Even after I cleared it. Going to do knock sensor soon. So what else can cause the code PO500. The car will not pass NYS Inspection with the check engine light on.

[lightsout]

VSS?what are the code definitions?

[SteveTheTech]

If you replaced the sensor and you are still detecting the code there are a few things it could be, none of them are very fun though. The ECM sets a PO500 when there is no speed signal detected to the computer while it knows it should be driving based on other inputs. Check your power supply, ground and speedo head. If the speedometer is not processing the signal correctly which is fed directly to the speedo head where it is converted in to digital pulse signal and then fed to the ECM.A problem anywhere in the circuit will cause the light to come on. What was the condition of the teeth on the old sensor?

[pjq45]

The old sensor I took out looked great. it had a green gear that looked fine.

[SteveTheTech]

Well that rules out a damaged transmission output shaft. It is more than likely an electrical issue. I would recommend getting it looked at unless you feel comfortable with you multimeter. The ESM on this forum http://www.nicoclub.com/FSM/ has the diagnostic information needed to pin down your issue.