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

Principles of Operation (How Does It Work?)

The Generic Electronic Module (GEM) constantly monitors its subsystems for concerns. If a concern is found in one of the subsystems, the GEM will record the concern in the form of a Diagnostic Trouble Code (DTC).

The ignition switch position is very important to the GEM functionality. Erratic or unexpected GEM functions can often be traced to problems with these GEM inputs.

The GEM controls a variety of systems:
^ windshield wipers
^ courtesy lamps
^ warning chimes
^ keyless entry
^ interior and exterior lamps
^ power windows