Speed Sensor questions
Thread Starter
Cruising
Joined: Jan 2021
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Speed Sensor questions
Hi, I have a 1990 corvette with the L98 engine. I have a question regarding the vehicle speed sensor wiring. I am wondering where I might look to get a kit to redo the wiring from the VSS to the ECM. The computer is throwing code 72 (Vehicle Speed sensor signal circuit error) and I've have read that this is most likely caused by faulty wiring from the VSS to the ECM. Would anyone know if there is a place I can get a kit to redo the wiring, or if I would need to DIY it. I have looked online and I haven't found a wiring repair kit for my specific year. Any feedback is much appreciated.
Team Owner
Joined: Sep 2003
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Hi, I have a 1990 corvette with the L98 engine. I have a question regarding the vehicle speed sensor wiring. I am wondering where I might look to get a kit to redo the wiring from the VSS to the ECM. The computer is throwing code 72 (Vehicle Speed sensor signal circuit error) and I've have read that this is most likely caused by faulty wiring from the VSS to the ECM. Would anyone know if there is a place I can get a kit to redo the wiring, or if I would need to DIY it. I have looked online and I haven't found a wiring repair kit for my specific year. Any feedback is much appreciated.
Thread Starter
Cruising
Joined: Jan 2021
Posts: 13
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It wouldn't be unusual for a '90 to have only a failed connector to the VSS at the transmission. There's considerable diagnostics required before you move forward. You can buy just the connector. If you've a failed VSS there's options to change the VSS to a different style that uses a different connector that through the years is thought to be much more reliable. Do you have in your hands a FSM (Factory Service Manual/Field Service Manual) maybe a Chilton or something other than what's considered to be more reliable?
Team Owner
Joined: Sep 2003
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I do not have a service manual or anything for the car no. Would you recommend getting one to see what the manual would have me do? And also if i do go ahead and just buy a new connector/VSS would you recommend changing to the different style VSS, and how do I look into changing it to the different style you suggested.
Last edited by WVZR-1; Jan 14, 2021 at 09:09 AM.
Le Mans Master
Joined: Aug 2015
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From: St. Charles MO
I may be missing something, but why would not assume the VSS itself is bad? Those have moving parts and can certainly fail, probably much more often than the wires or wiring connectors. Have you definitively rule that out?
Team Owner
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Le Mans Master
Joined: Aug 2015
Posts: 6,120
Likes: 1,997
From: St. Charles MO
I didn't mean for the OP to start throwing parts at the car, but rather to do a couple simple diagnostic tests. With a VSS, I'd pull it and test for alternating current when it is spun. Then it needs to be tested for resistance across the terminals (it can still make alternating current even if resistance is off the charts). That's how I diagnosed mine in my 96 when it went bad. That said, Rockauto carries three different VSSs for a 90 Corvette and all of them are under $30. So it's not a very expensive "throwing-parts" attempt, either.
Last edited by MatthewMiller; Jan 14, 2021 at 04:22 PM.
Team Owner
Joined: Sep 2003
Posts: 25,398
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I didn't mean for the OP to start throwing parts at the car, but rather to do a couple simple diagnostic tests. With a VSS, I'd pull it and test for alternating current when it is spun. Then it needs to be tested for resistance across the terminals (it can still make alternating current even if resistance is off the charts). That's how I diagnosed mine in my 96 when it went bad. That said, Rockauto carries three different VSSs for a 90 Corvette and all of them are under $30. So it's not a very expensive "throwing-parts" attempt, either.
here's some 'self inflicted' damage often experienced removing an original early VSS.
https://www.corvetteforum.com/forums...-question.html
Here's an eBay link with a correct fabrication that you might like to compare.
https://www.ebay.com/itm/NEW-OUT-OF-...sAAOSwzRRf540I
If it's actually an 'original' center connect VSS the first inexpensive attempt I'd think should be this connector BUT maybe sourced locally and shouldn't be an issue! This would be truly the only 'inexpensive' first purchase! The only! This connector facilitates very easy diagnostics.
https://www.ebay.com/sch/i.html?_fro..._odkw=12126452
Last edited by WVZR-1; Jan 14, 2021 at 09:15 PM.
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Le Mans Master
Joined: Aug 2015
Posts: 6,120
Likes: 1,997
From: St. Charles MO
If it's an original 'center connect' VSS it's often destroyed by anyone not familiar with the fabrication. RA again!
here's some 'self inflicted' damage often experienced removing an original early VSS.
https://www.corvetteforum.com/forums...-question.html
Here's an eBay link with a correct fabrication that you might like to compare.
https://www.ebay.com/itm/NEW-OUT-OF-...sAAOSwzRRf540I
If it's actually an 'original' center connect VSS the first inexpensive attempt I'd think should be this connector BUT maybe sourced locally and shouldn't be an issue! This would be truly the only 'inexpensive' first purchase! The only!
here's some 'self inflicted' damage often experienced removing an original early VSS.
https://www.corvetteforum.com/forums...-question.html
Here's an eBay link with a correct fabrication that you might like to compare.
https://www.ebay.com/itm/NEW-OUT-OF-...sAAOSwzRRf540I
If it's actually an 'original' center connect VSS the first inexpensive attempt I'd think should be this connector BUT maybe sourced locally and shouldn't be an issue! This would be truly the only 'inexpensive' first purchase! The only!
