Just purchased an 06 Z51 Corvette Coupe last week. Everything was working fine and then all of a sudden the speedometer fluttered and went to ZERO. All other gauges continued working. Went out the next day and the speedometer was working and after about driving 10 miles, same thing happened. Can anyone point me in the right direction as to what may be causing this issue? Thanks in advance

 

First place to check is probably the VSS - vehicle speed sensor. It could also be a poor connection between the VSS and the speedo.

 

Thank you. Where is the VSS located?

 

Not liking this on a just purchased car.

 

I agree. Previous owner had the car at his local Chevrolet dealer for this problem. Charged him $300 but still did not fix it.

 

The VSS sensor is on the top of the differential passenger side, just off center line on the rear top of the diff.



Could be a connector coming loose, or could just be the sensor is going south. Hence sensor works off a magnet, and that magnet goes weak over time.

The Vehicle speed sensor is only $40, and on a 06 with some mileage to it, not uncommon for it to need to be replaced due to age with its internal magnet going weak.
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If the sensor it still good, then pull the battery to get to the C184 connector next to it to disconnect it from it self, disconnect the VSS sensor connector and ground those connector pins out to each other on the VSS connector with a paper clip, then go to the C184 connector disconnected on the female side that leads back under the car with meter and check the wire continuities of wires going back to the VSS connector see if one of the wires has a broken wire. Gm used wire that is way under sized to save money of a few wires, and some of the wires tend to break with just enough age to start with.
Note, if you need the wiring pinning of the C184 connector, let me known and I can give you a link to download it. But all you really need to do it find the color of the wires at the VSS connector, and match them up on the C184 connector to know which pins to probe on the C184 connector.

If you have continuity on all the wires, then need to check the other side of the C184 male side of the connector that leads down to the ECM isntead. Some times, it just the C184 connector needs to be spray contact cleaned to solve corrosion problems as its pins, while other times, it the ECM connector that has the corrosion problem isntead.



To get to the ECM connector, remove the left passenger tire, pull the centers out of the rear wheel well liner studs to pull them out, and on the bottom of the rear well cover, will have 3 bolts on the bottom that you need to removed as well,


If you do have a broken wire, then the fun it about to start to repair the wire.

The C184 wire loom runs under the A/C lines in front of the firewall, then down the passenger side of the torque tube tunnel, and at the torque tube center of loom, there is an stiffer outer shielding that supports the loom to the side of the torque tube clip points. So most likely if the wire is cracked/broken, its at the start point of the stiffer in the torque tube tunnel.




To get to the wire loom if at that spot, you have to get the car on a lift, pull the exhaust X pipe and the passenger side cat down pipe, which will now allow you to remove the Torque tube cover to get to the loom.

The C-184 connector had enough slack in it that it can be pulled towards the torque tube tunnel and with the stiffer backer section unclipped, it will droop the loom down far enough to make quick repair of the broken wire.

Also to point out, once to you get to the entire loom, you can put a signal generator on the wire in question, and using a signal probe, you can trace tone down the outside of the loom until you lose tone to find the cracked wire as well. Some times you luck out and it just the VSS connector that has the problem, or the broken wire in the back of the car loom that you can get to without dropping the torque tube cover, but most of the time, it at the point right before the stiffener at the torque tube that you have the broken wire problem. This is do to the loom pinch point at the tunnel stiffener, and the heat that is coming down the torque tube from the motor as well.

As for replacing the entire C184 loom with a New OEM one to get in front of future problems, Don't!!!!
Send the old loom out to be rebuilt or rebuild it yourself, and this time with wires that are not so small in gauge, they are just going to cause problems again. It not all the wires that are too small in gauge, but a few that are just single source wires back to the ECM that have the heat/pinch point problem to cause them to break.

 

Is your car stick or auto?nothing in your profile

 

6 speed manual

 

To add, to weed out the problem at the dash/ICP itself, you can put a tech II on the car, and drive around.

The VSS signal is sent to the dash via the GM land bus, so if it just the dash, then the Tech II should still be able to pick up the signal begin sent to the dash, if the VSS is working correctly and does not have bad wire problem to start with.

 

I know this is a very old post, but it is dealing with my topic. I pulled out the stock head unit and replaced it with a new stereo. Every connector that went into the stock unit was not used. Is there anything, connection wise, that would link the stereo with the speedometer and odometer? As soon as I put in the new stereo, the speedo and odometer stopped working. All other gauges are fine. Definitely not a coincidence and has to be related. I just cant imagine how the stereo has anything to do with the speedometer.

 

There is a VSS signal wire in the radio harness for the Factory GPS radio. If this is shorted to ground or battery it could stop the speedometer from working.
I think it is a green wire in the harness for the VSS signal.
Check your wiring diagram for the new stereo and interface adapter to verify which wire is VSS.

Gary