So I just bought my car and was driving it home, everything going well, then I stop to get some food. When I started the car up, the ABS and ESP lights were on, started driving and the speedometer didn't work. Okay, so I check the code and it says the vehicle speed sensor is bad. Drive for a while using the GPS and rpm for speed. turning the car off and back on did nothing to change this. Next morning I start the car up and the speedo works and lights are off. drive it gently, shut it down and start it up again- speedo still works. Shut it down, drive it agressively and the next time the speedo doesnt work (with the lights). At this point I start reading the forums for an answer- a few things it could be- bad ABS module, or a bad speed sensor, or a broken magnetic inductor ring, and one person mentions that theirs would do this if the trans was low on gear oil.

I start gearing myself up for removing the module and soldering it (I've built a megasquirt and other stuff so it doesn't faze me).

I decide- heck, i might as well get the transmission oil and diff oil changed as I doubt they ever have been and the car has 182,000 miles. Take it to the shop as I don't feel like buying the specialty hex bit for the drain plugs.

Problem hasn't come back since- driving it rough or gentle, hot or cold it's been perfect since....

Coincidence? Or perhaps the vss needs the gear oil to be around the sensor and the inductor ring? Or maybe there was just enough metal particles in the gear oil that it interfered with the sensor? The shop said the fluid was dark, but not metallic at all.

Or maybe it's just pure luck and the module will go haywire again in a few days...

I'll post an update if it happens again.

 

Interestingly enough it is still working just fine- there was one time where it did the same thing, but on turning it off and back on it went away and hasn't come back since.

 

the same thing happened to me. the next day ABS/EPS lights off and speedometer working fine....i have an appointment for it be looked at but I'm thinking of canceling and see if it re-occurs...i have a 2003 A4 1.8t with 151,000 miles....any suggestions?