Circuit/System Description

WARNING: This page is about a different car, the 2007 Suzuki XL7. However, it is still accessible from the selected car via links, so may be relevant.

The accessory voltage circuit is a positive voltage signal to wake up the from the body control module (BCM) to the engine control module (ECM) and the transmission control module (TCM). The signal is activated in 2 ways; any time the ignition switch is in the ACC or RUN position, or anytime the body control module (BCM) determines that communication is needed from the powertrain. When the ignition switch is in the ACC or RUN position, the accessory voltage circuit input from the ignition switch to the BCM is internally connected to the accessory voltage circuit output, and voltage is supplied to the modules. The BCM also supplies voltage to the accessory voltage circuit when it determines that communication is necessary with the powertrain and the ignition is not in the ACC or RUN position such as during remote start.