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)

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Dual Plug Inhibit System

PURPOSE
Dual Plug Inhibit (DPI) allows the Powertrain Control Module (PCM) to switch the ignition system from single to dual plug operation.

OPERATION
During cranking the vehicle is in single plug mode (only the plugs on the right side of the engine are firing). The PCM sends a command to the Distributorless Ignition System (DIS) module to switch to the dual plug mode (both plugs in each cylinder are firing) when the engine is started.