1987 Corvette Speedometer not reading correctly
Thread Starter
1st Gear
Joined: Mar 2026
Posts: 1
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1987 Corvette Speedometer not reading correctly
Hello everyone,
I currently drive a 1987 C4 Corvette Coupe (Automatic transmission). When I drove it yesterday I saw that the speedometer only ramps up to 7KM/H when driving. i tried it at multiple speeds and i also switched to MPH which is also stuck. The rest of the meters are working fine. I gave the computer a hard reset, disconnected the car battery and re-connect it and I had a look at the fuse which was all oke. I am quite new with the corvette so does anybody have any advice? Thank you very much
I currently drive a 1987 C4 Corvette Coupe (Automatic transmission). When I drove it yesterday I saw that the speedometer only ramps up to 7KM/H when driving. i tried it at multiple speeds and i also switched to MPH which is also stuck. The rest of the meters are working fine. I gave the computer a hard reset, disconnected the car battery and re-connect it and I had a look at the fuse which was all oke. I am quite new with the corvette so does anybody have any advice? Thank you very much
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
The digital cluster gets MPH directly from the vehicle speed sensor (VSS) in the transmission. Only after the cluster has processed the VSS signal does it make its way over to the ECM. You may want to start by testing the VSS itself, or disconnecting it and spraying the connectors with some electrical contact cleaner.
Racer
Joined: Jul 2012
Posts: 400
Likes: 161
From: Ellicott City MD
I had the same problem this weekend with my 92 ZR-1. Driving to cars and coffee Sunday morning at a constant 65 it started reading 62, 55, 45, 61......all over the place. It is the speed sensor and I have a replacement on order at RockAuto right now. It is located on the tail end of the transmission. Good luck and keep us posted.
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
I had the same problem this weekend with my 92 ZR-1. Driving to cars and coffee Sunday morning at a constant 65 it started reading 62, 55, 45, 61......all over the place. It is the speed sensor and I have a replacement on order at RockAuto right now. It is located on the tail end of the transmission. Good luck and keep us posted.
