Operation CHARM: Car repair manuals for everyone.
Home >> Cadillac >> 1992 >> DeVille V8-300 4.9L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Vehicle Speed Sensor >> Testing and Inspection >> Symptom Related Diagnostic Procedures
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Symptom Related Diagnostic Procedures

Enter on-board diagnostics for vehicle speed parameter number P.O.9. Drive vehicle or simulate vehicle speed using vehicle speed signal generator (GM J-38522). Observe Speedometer and compare it to vehicle speed shown on Fuel Data Center (FDC) display.
^ If both Speedometer and FDC display indicate same speed, check wiring routed to/from Vehicle Speed Sensor that may be next to ignition (spark plug) wires.
^ If FDC display and Speedometer do not display same speed, check wiring to Instrument Cluster and tires for correct size and inflation. Also check all applicable terminals at in-line connectors and at Instrument Cluster connector for proper terminal contact. Refer to TECH TIPS for inspection/repair procedures. If OK, replace the Instrument Cluster.
pro multis · About Operation CHARM