Tweet
My 95 GRAND-AM, while sitting in park sometime when I rev the engine the speedometer will move and the SES light comes on and the code is for VSS. What would cause this? The speedometer works normaly while driving. Thank you for any help.
-
-
Double check that spark plug wire routing is per current factory wire map. Also, check that your grounds are good all around. Then we can go crazy finding your bleed.
If you ain't rock and roll, you must be driving a Honda -
Maybe cross-talk from the ignition system? The VSS is pretty close to the 3x crank sensor and might even share the same wire routing. How fast is the speedo indicating at what rpm? My manual states the VSS gives 4000 pulses per mile of travel.1995 Grand Am SEComment
-
Azrael: the PCM converts the VSS's high PPM(can't remember an exact number for a 95GA, but it's the number of revolutions the stock tire makes in a mile multiplied by the number of notches in the VSS reluctor ring) down to 4K PPM for use by the instrument cluster.
that being said, i've done this before... i believe it's always a "VSS Low" code. i haven't tried it since, but i pulled my full harness to make some proper repairs to it and i decided to twist the hell out of the wires where they come out of the main loom near the A/C compressor, thinking it will help.Comment
-
Thank you all for your replies. I will check to see if the ignition is jumping over and I will clean the grounds. Do you think it would help to twist the wires going to the VSS? While in park the speedometer will jump to @15mph at @3000rpm. I don't know if it is related but I also had a code for the camposition sensor but that one cleared off and didn't come back.Comment
-
see, i started having that code too the summer before i went OBD1... or maybe it was the 24X....
either way, it sounds like there is some EMI finding it's way into the sensors...( i believe mine was caused by VERY low resistance plug wires)
and twisting can't hurt, it's a somewhat effective shield, that's why GM did it with the 3X crank sensors as well, twisting a minimum of 9 times per foot...Comment
Comment