Circuit Description

WARNING: This page is about a different car, the 2005 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

The Run/Crank relay is controlled by the body control module (BCM). The Run/Crank relay contacts are supplied a hot at all times from the fuse block underhood. The relay supplies power to several components when the vehicle is in the RUN or CRANK power mode. This signal is labeled Ignition 1. When the ignition switch is placed in the RUN or CRANK position, the BCM will receive a Run/Crank signal from the ignition switch and turn ON the Run/Crank relay. When the ignition switch is in the OFF position, the BCM will turn OFF the Run/Crank relay. The powertrain control module (PCM) compares the Run/Crank relay output signal with the BCM Class 2 serial data power mode message. If the ignition 1 voltage signal and the power mode message do not match for an allotted time, the PCM will disable the fuel injectors and DTC P2535 will set.