Circuit Description

WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

Moving the ignition switch to the start position signals the body control module (BCM) through discrete inputs from the ignition transducer that engine crank has been requested. The BCM verifies that theft is not active and sends a serial data message to the engine control module (ECM) requesting engine start. The ECM receives a ground signal from the park/neutral position (PNP) switch or a signal from the clutch pedal position sensor notifying that it is safe to start the engine. Ground G105 supplies ground for the CRNK relay coil. The starter relay coil control circuit is then supplied voltage by the ECM closing the switch in the starter relay suppling 12 volts from the CRNK fuse to terminal A of the starter. Ground is supplied to the starter solenoid through the engine block.