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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EGR Control Solenoid: Description and Operation

The EGR vacuum control has a vacuum control solenoid that uses "Pulse Width Modulation" (PWM). This means that the ECM turns the solenoid "OFF" and "ON" many times a second and varies the amount of "ON" time (pulse width) to vary the amount of EGR. The ECM may use inputs from the following sensors to regulate the solenoid.

^ Coolant Temperature Sensor (CTS)
^ Throttle Position Sensor (TPS)
^ Mass Air Flow (MAF) sensor