Circuit/System Description
WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) controls engine cranking based on a power mode input and the status of the clutch pedal position (CPP) sensor (Getrag M86 / Saab MU3), or the park/neutral position (PNP) switch (MN5 4T45-E). With the transmission in park or neutral, voltage at the ECM PNP switch signal circuit is low, or the CPP signal circuit indicates that the clutch pedal is pressed. This indicates to the ECM that conditions are acceptable for cranking. The ECM provides voltage to the starter relay coil control circuit. The relay provides voltage to the starter terminal A X1 and engages the starter solenoid.