Operation CHARM: Car repair manuals for everyone.
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

Diagnostic Strategies

This system shares diagnostic procedures with the Computers and Control Systems. Refer to Computers and Control Systems / Testing and Inspection / Procedures / Trouble Code Diagnostic Charts when testing this system.




When trying to verify a speed control system electronic malfunction, connect a DRB scan tool, if available, to the data link connector. The connector is located at left side of the steering column, and at lower edge of the panel.

A speed control malfunction may occur without a diagnostic code being indicated.