Corvette C6 jerky speedo
Thread Starter
5th Gear
Joined: Aug 2018
Posts: 5
Likes: 0
Corvette C6 jerky speedo
Hi all!
First of all, warm greetings from Sweden and thank you for a awesome board. I think I have solved over 5 common faults on my car just reading this boards, and learned tons about corvettes, tuning and so on.
i have some strange problems left, and one that I can’t find on the board is about my speedometer.
Everything is working , but it is really jerky and jumps up if you accelerate/deaccelate. For example, if you hit the throttle going 0-60 mph, it will jump up on its way like ,30-40-55-60, and when I hit 60, it will take a half / a second to keep up the speed and stable. If I brake to 0, it will be 15-20 when I stand still, and then fall down to zero with same delay. (It’s little like jerky slow motion) super annoying!
When you start the car and the speedo sweeps, it looks smooth all the way. But as soon you drive, it will be jerky. It behaves the same on mph/kmh when I switch in options.
i tried to make a short video on it, but it is very hard to see. If you drive the car you can’t miss it. Here is the YouTube link(too large for attach)
Could it be the dash cluster , or is there other things you think it is?
Thanks a lot!
/Jimmy
First of all, warm greetings from Sweden and thank you for a awesome board. I think I have solved over 5 common faults on my car just reading this boards, and learned tons about corvettes, tuning and so on.
i have some strange problems left, and one that I can’t find on the board is about my speedometer.
Everything is working , but it is really jerky and jumps up if you accelerate/deaccelate. For example, if you hit the throttle going 0-60 mph, it will jump up on its way like ,30-40-55-60, and when I hit 60, it will take a half / a second to keep up the speed and stable. If I brake to 0, it will be 15-20 when I stand still, and then fall down to zero with same delay. (It’s little like jerky slow motion) super annoying!
When you start the car and the speedo sweeps, it looks smooth all the way. But as soon you drive, it will be jerky. It behaves the same on mph/kmh when I switch in options.
i tried to make a short video on it, but it is very hard to see. If you drive the car you can’t miss it. Here is the YouTube link(too large for attach)
Could it be the dash cluster , or is there other things you think it is?
Thanks a lot!
/Jimmy
Thread Starter
5th Gear
Joined: Aug 2018
Posts: 5
Likes: 0
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
VSS sensor is on the top of the diff. You can find it by looking at the black wiring harnness that goes back to the diff in the below photo.
As for when the VSS is going out, you will have not speed reading or slugish speed reading at slower speeds, then the needle will jump to the correct speed as your going faster. Since your speedo is set to Km, then your problems at below 30KM would be the VSS going out.
Also to note, since the VSS is really just a magnet that is picking up pulses off the ring, it not uncommon for the magnets in then to go weak in say 10 year'sih, and sensor needing to be replace.
As for when the VSS is going out, you will have not speed reading or slugish speed reading at slower speeds, then the needle will jump to the correct speed as your going faster. Since your speedo is set to Km, then your problems at below 30KM would be the VSS going out.
Also to note, since the VSS is really just a magnet that is picking up pulses off the ring, it not uncommon for the magnets in then to go weak in say 10 year'sih, and sensor needing to be replace.
Last edited by Dano523; Aug 4, 2018 at 09:16 AM.
Thread Starter
5th Gear
Joined: Aug 2018
Posts: 5
Likes: 0
VSS sensor is on the top of the diff. You can find it by looking at the black wiring harnness that goes back to the diff in the below photo.
As for when the VSS is going out, you will have not speed reading or slugish speed reading at slower speeds, then the needle will jump to the correct speed as your going faster. Since your speedo is set to Km, then your problems at below 30KM would be the VSS going out.
Also to note, since the VSS is really just a magnet that is picking up pulses off the ring, it not uncommon for the magnets in then to go weak in say 10 year'sih, and sensor needing to be replace.
As for when the VSS is going out, you will have not speed reading or slugish speed reading at slower speeds, then the needle will jump to the correct speed as your going faster. Since your speedo is set to Km, then your problems at below 30KM would be the VSS going out.
Also to note, since the VSS is really just a magnet that is picking up pulses off the ring, it not uncommon for the magnets in then to go weak in say 10 year'sih, and sensor needing to be replace.
thanks a lot for your awesome replie.
Just to be clear the speedo doesn’t go smooth in higher speed either.
Dont know if you misread or I did explain to bad.
i will order it and test, about 60 $ with shipping.
i will report and come back when I changed it
Regards Jimmy
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
Lets get this out the way, and the speedo is not analog in any of it functions, but all digital instead. Here there is a small motors that makes the dials move in the cluster.
The information for the cluster is sent to it via the Gm lan bus. Take the voltage that the dash is reading, and that is the ECM voltage, not the cluster voltage reading instead.
So could be the VSS going out to cause the dodgy information to begin with, could be a problem in GM land bus connection to the cluster, or could be a bad VSS sensor isntead.
How to tell if it the dash cluster that is having the problem, watch the dial sweeps as start up, and if the slweeps are smooth, then you can weed the cluster motors out as the problem. So this would lead you back to either VSS going out, or you have bad GM land bus connector problems isntead.
The information for the cluster is sent to it via the Gm lan bus. Take the voltage that the dash is reading, and that is the ECM voltage, not the cluster voltage reading instead.
So could be the VSS going out to cause the dodgy information to begin with, could be a problem in GM land bus connection to the cluster, or could be a bad VSS sensor isntead.
How to tell if it the dash cluster that is having the problem, watch the dial sweeps as start up, and if the slweeps are smooth, then you can weed the cluster motors out as the problem. So this would lead you back to either VSS going out, or you have bad GM land bus connector problems isntead.
Thread Starter
5th Gear
Joined: Aug 2018
Posts: 5
Likes: 0
Lets get this out the way, and the speedo is not analog in any of it functions, but all digital instead. Here there is a small motors that makes the dials move in the cluster.
The information for the cluster is sent to it via the Gm lan bus. Take the voltage that the dash is reading, and that is the ECM voltage, not the cluster voltage reading instead.
So could be the VSS going out to cause the dodgy information to begin with, could be a problem in GM land bus connection to the cluster, or could be a bad VSS sensor isntead.
How to tell if it the dash cluster that is having the problem, watch the dial sweeps as start up, and if the slweeps are smooth, then you can weed the cluster motors out as the problem. So this would lead you back to either VSS going out, or you have bad GM land bus connector problems isntead.
The information for the cluster is sent to it via the Gm lan bus. Take the voltage that the dash is reading, and that is the ECM voltage, not the cluster voltage reading instead.
So could be the VSS going out to cause the dodgy information to begin with, could be a problem in GM land bus connection to the cluster, or could be a bad VSS sensor isntead.
How to tell if it the dash cluster that is having the problem, watch the dial sweeps as start up, and if the slweeps are smooth, then you can weed the cluster motors out as the problem. So this would lead you back to either VSS going out, or you have bad GM land bus connector problems isntead.
Thanks again
