1989 Chevy Cavalier Trouble code 24

Tiny
AZTROPIC
  • MEMBER
  • 1989 CHEVROLET CAVALIER
Computer problem
1989 Chevy Cavalier 6 cyl Front Wheel Drive Automatic 190K miles

1989 Chev cavalier Z24 2.8 automatic always sets code 24(VSS) after it is warmed up, and within 3 to 5 seconds after coasting above 50 MPH (digital dash) Over the years, I have replaced every possible sensor including a different throttle body and computer with absolutely no change. Begining to suspect something mechanical like a broken or grounded wire or vacuum leak. Any ideas? Any list of conditions that need to be met before triggering code 24?
aztropic
Sunday, August 29th, 2010 AT 12:55 PM

4 Replies

Tiny
DOCFIXIT
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With DVOM on AC scale mearure voltage across VSS sensor on transaxle. Jack up in gear if voltage present then check at ECM
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Sunday, August 29th, 2010 AT 1:44 PM
Tiny
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Nope! Definately not a computer problem. Tried a brand new one and a known good one from a friends car with the exact same results.
Would be interested in knowing the parameters that cause a code 24 to be set.(Vehicle speed, voltage at throttle position sensor etc.)
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Sunday, August 29th, 2010 AT 11:04 PM
Tiny
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Will check for AC voltage at ECM. (Digital dash speedometer works fine) Thought speedometer # MPH was created by the ECM from VSS voltage signal?
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Sunday, August 29th, 2010 AT 11:22 PM
Tiny
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Only two things set code 24 faulty VSS or PROM


https://www.2carpros.com/forum/automotive_pictures/198357_Graphic_589.jpg

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Monday, August 30th, 2010 AT 1:58 PM

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