Engine Controls - Diagnosing DTC 24 (VSS)

9218chevy06

Number: 90-174-6E

Section: 6E


Date: February 1990

Corporate Bulletin No.: 016508


Subject:
DRIVEABILITY AND EMISSIONS INFORMATION FOR COMPONENTS SETTING CODE 24


Model and Year:
1988-90 B CAR WITH 5.OL (VIN CODE Y) ENGINE


TO: ALL CHEVROLET DEALERS

This bulletin applies to Section 6El "Driveability And Emissions" to 1988, 1989 and 1990 Service Manuals with 5.OL "B" (VIN Y).

This bulletin serves to improve diagnosing Code 24 (Vehicle Speed Sensor). If a Code 24 problem is still present after completion of the trouble code chart, then the following Diagnostic Aid should be checked. The convenience center and reminder package (if equipped) or timer module should be disconnected and then note if the fault is resolved. A short in any of the previously mentioned modules or wire common with Circuit 437 can set a Code 24. Refer to Section 8A, Page 33-0 for more information on this circuit and vehicle speed sensor.